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BWSSB Rain Water Harvesting rules

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Folks,  The draft rules for the BWSSB Rain Water Harvesting Amendment Act 2009 have been published on the BWSSB website.  They have generously provided one whole week for feedback from the general public. See the rules here.

Please review the rules if you are interested.  I am not sure how detailed "rules" are supposed to be? My understanding is that the rules are what translate the intent of the act to practice.

However, a first reading is disappointing to me.  The rules do not specify any standards for the design or qualifications for a designer. Linking the design to a published standard, if available.  There is no clarity of how "quality" will be ensured.  There is no clarity on what percentage of built up area should be harvested.  Will someone who harvests from part of their roof qualify?  What if the RWH system goes into disuse after a certain number of years.

Original amendment can be found here:

The key text of the amendment is as follows:

“72A. Obligation to provide rain water harvesting structure.- Within nine months from the date of commencement of the Bangalore Water Supply and Sewerage (Amendment) Act, 2009, every owner or occupier of a building having a sital area of 2400 square feet and above or every owner who propose to construct a building on a sital area of 1200 square feet and above, shall provide for rain water harvesting structure in such manner, with such conditions as may be provided in the regulations, failing which the Board may cause such rain water harvesting structure and recover the cost from the owner or occupier, as the case may be, as arrears of land revenue".



RKCHARI's picture

RWH Rules

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Hi SanjayV,

I am submitting some additional inputs to ensure concerns of quality and qualification of persons installing the unit for the home owner is addressed. It is not just a question of collecting water from roofs and open areas, filtering and storing. There is a science behind the entire process to get maximum mileage from this God given gift. Let me see how best I can address these issues.

Similarly for infiltration and ground water table recharge. It has to be done scientifically capturing 100% and ensuring 0% runb-offs.

Shall keep Prajagalus in the loop.




thampan's picture


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A quick feedback based on single reading of the rules.
  1. Section 7 & 8 of the document seem to be a repetition.
  2. The rules talk about "owner who constructs", it does not talk about builders who construct apartments etc. These rules may be questioned later, since apartment owners typically will not have 1200 sq ft of land in their name. Hence rules should be modified to bring in the aspect of shared housing.  ( any construction within a plot area of 1200 sqfts or more should have water harvesting installed by the owners individually or collectively) ( appliable to apartments, housing colonies etc)
  3. The rules assume storage for 2 cm of rainfall ( roof top). Is this adequate ? ( similarly 1cm for ground)
  4. any covered land ( concrete, tar etc) should be considered similar to roof tops (open cemented parking lots etc)
  5. at least, Quality of water used to recharge through borewells should be specified as it is going directly into the water table. ( i have not had a look at IS10500)
  6. the document uses the term appropriate - to clarify what is appropriate and what is not, examples should be specified so that the courts can interpret better in case of dispute.
  7. the only penal action specified is that BWSSB can build RWH systems and levy the cost from the owners. In addition to this BWSSB should have authority to charge fines ( which could be compounded with time) ( to be fixed in the rules) till such systems are installed and then charge the cost of the system.  This will ensure that the citizens will install RWH systems.
  8. The period of 9 months is a short time period for existing constructions. This should be extended to, say 2 years.


Sanjay, would be great if you could coordinate to collect feedback from praja and send it.

Tarle, hoping to hear from you on this.

thampan's picture

few more comments

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  1.  to ensure effective implementation, BWSSB approvals should not be given to any new project ( if RWH is applicable) without RWH in the plans after 12 months of these rules being applicable.
  2. for existing constructions, the owners should be mandated to submit the master plan for RWH within one year of the rules being applicable and implementation within two years.
  3. There should be a competent authority setup to review the plans and inspect RWH installations.
  4. The efficacy of RWH installations should be measured through self submissions and random checks
sanjayv's picture

Will send compiled comments

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 Please post your views and have a vigorous discussion. Like it or not, this law will directly impact almost all of us.  So imagine that you have to install a RWH system within 9 months (if one is not already present). What is required so that this will be a robust practice for years to come. The amendment conveniently put everything on the framed "rules and regulations".  I will do the job of compiling and sending to BWSSB.

Does anyone here  have any knowledge of how the Chennai experience went?  What were the learnings there?

RKCHARI's picture

Some Format Suggestions

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How about something like this?


Suggestions to Rules & Regulations for Rainwater Harvesting Systems Mandatory Implementation
1.      Point 2 (Viii): “Ground Water Recharge” means infiltration of water to enhance aquifer levels;
Point 2 (ix): Rainwater Harvesting means a system to scientifically collect as much of rainfall as possible (preferably 95% to 100%) from total catchment area (including roof tops and all open areas around building), filtering it to remove microbial pathogens and floating particles when storing for potable use and ordinary sieve filtration when water is being stored for secondary use;
2.      Point 3: Rainwater Harvesting Scheme Implementation:
i)Roof based rainwater harvesting shall mean collection of 100% of rainfall after removal of first flush contaminants preferably through natural green process of roof gardens, storing in tanks made preferably in recycled material like polypropylene etc, stored preferably underground (to ensure UV effect does not lead to photosynthesis and algae formation within the tank and that water is stored in cool, dark environs with proper aeration through capillary action) and accessed through simple pumping action directly to taps or through overhead tanks;
ii) Land based rainwater harvesting / storm water infiltration shall mean collection/infiltration of 100% of rain that falls on all open lands surrounding the building for retention and re-use or for recharging aquifers to increase groundwater table level.
3.      Point 4: (A) Roof Based Rainwater Harvesting:
(a)   If Rainwater Harvesting is done for the sole purpose of collecting water for all primary / potable use like drinking and cooking, it should conform to IS 10500 standards or better;
(b)   If however Rainwater Harvesting is done for reuse for secondary purposes like gardening, toilet flushing, washing clothes and utensils and car washing etc, normal filtered water with no apparent contaminants like leaves and insects would suffice;
4.      Point 4: (B) Recharging Groundwater Table:
(a)   All Rainwater Harvesting done for purpose other than for re-use, should be infiltrated within the catchment area to recharge aquifers preferably through pervious surfaces; care should be taken to infiltrate only treated / clean water and not any form of contaminated water;
(b)   Design Criteria: Whether rainwater is being collected for re-use or infiltration, the design of the entire system should preferably be to ensure maximum efficiency in the quantum collected, both from roof tops and surrounding land within the catchment area;

I have not touched on other legalese issues - just stuck to wording the technical aspect more scientifically.

Happy more suggesting!



thampan's picture

RKC sir

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My thoughts are 

1) 100% collection cannot be ensured and hence should not be put into the law. It already contains guidelines for the volume to be processed.

2) specifics of tank design etc should not be mentioned in the law as there can be competing alternatives.

gurudas.s's picture


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This is a typical Govt. order without head or tail. As questioned by Mr. Muralidhar the order does not specify many salient aspects to bring in clarity.

I have another take. What is the responsibilty if the BWSSB apart from checking whether the order has been followed or not? Should it not involve itself aggressively by suppling directly or through certified agencies quality filters of various sizes, arranging for certification of the quality of water being stored etc.?

It is high time organisations and the media intervened at this early stage itself.



I do support the action of SI Srinivas and support nominating him for recognition as an honest & deserving Govt. official for performing his duty in the right spirit.


tsubba's picture


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thampan. agree.

also one of the things i am trying to understand what is the objective of bwssb?

ideally, people would do it to on their own AND for their own benefit. if they are doing it for their own benefit, then specs dont matter. the only specs then that are necessary are those that dodnot effect community - which is what is govts concern.

what i dont know is why people dont do it. what are the issues? when something like solar water can catch up. why cant rwh?

how can bwssb encourage people to reuse the resource that is available to them? one thing they can do is offer engineering expertise that helps people maximize their utilization. what else can they do? 1 week is way too less to discuss all this.

bigger entities like mall, thetaters etc etc should be mandated. and their implementation checked. every year they know how much rain fell. so they should be able to estimate how much water is available at say 70% effieciency. then they know how much they metered at bwssb. using this they can impose a fine/ levy for non environmental practices.

thampan's picture

public good v/s private good

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Solar water is a private good. I install a solar geyser, I save on electricity, I get hot water.

Water table is a public good, I do RWH, water table gets better, my neighbor has a water supply business, he earns money.

Hence need for compliance measures. 


tsubba's picture

re: Pg vs. Pg

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yes t,

but 99% of water from my compound is already going into the public drain infront of my house. why should i invest to increase the water table? i am  giving the govt water, why dont they direct it to the table?

the way i see it, i will implement rwh so that i can use it for my own purposes, when i want it. instead of giving it to govt. who are anyway not likely to use it meaningfully. why give the water to govt, when i can use it for my own purposes?

RKCHARI's picture

RWH Rules & My Take on Comments Hitherto

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1. 100% harvesting can be ensured if RWH system is properly installed. Making it into law will ensure people do not put up "naam-ka-vaste" units to avoid penalty.

2. Agree, specs of tanks need not be mentioned.

3. Two major reasons for people being reluctant to go in for RWH systems inspite of apparent usefulness lies in : (a) No single-window supplier of the entire system including calculating size of retention tank capacity properly, which is critical to cost; please look up thye yellow pages and call anyone listed as RWH system supplier - none will provide one-stop-shop service; (b) No indigenous system provides drinking quality water or even plain and simple good quality water, properly stored in hygienic conditions.

4. We all seem to sincerely believe that harvesting rainwater is not a scientic system and that merely collecting it in buckets when it rains is as good. This is truly a complete misnomer and smacks entirely of lack of knowledge about what is happening in advanced / developed countries. When any of us travel abroad for work or on pleasure, do we ever take the trouble of asking any of our friends or hosts whether they have a RWH system in place at their homes / offices? This is the last thing on anyone's mind - we only ask about availability of this or that gadget and run towards glitzy malls!

5. Part of BWSSB manadate should be to give RWH wide publicity so that everyone, from high-end villa owners to those staying in jhuggies and jhonpuries realise that water is finite and one day we will have to depend solely on rainwater for our very existence.

5. Arguments about groundwater recharge not being beneficial to anyone personally is untenable as we must all realise that this earth belongs to all of us and everything in it is for common good. It is the midset of people not wanting to do things for the community which must be broken. This is one aspect of Indian culture which is so deep seated that no amount of influence from West oe East appears to shake our selfishness. Community living is something we have just not learnt. Small attempts like Praja forum where we at least discuss our lack of civic sense is really a drop in the ocean of problems we face collectively.




tsubba's picture

chari sir's post

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i hope the discussion here does not get hijacked around the contentious points 4 and 6 of chari sir's post. lets just stick to relevant issues. appeal to idealism and problematizing entire peoples and their communities, and trying to shame them etc.,  and other such philosophical niceities lets leave all these to the politicians and social "scientists" and other "thinking", "sensitive" people. lets just stick to empirical ideals.

if i dig a whole what is achieved. where all to dig. how all to dig. what all to use to dig. and so on.

so comming back to topic. isnt reuse of water for secondary and tertiary purposes an honourable goal? thampan, i am thinking there is an analogy here - with the family planning thingie. how and why a good number of people internalized that and started implementing it voluntarily.

RKCHARI's picture

TS  Sir How can one

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TS  Sir

How can one compartmentalise life? Why leave the very mindset and attitude out and just talk about nuts and bolts?

Is it convenient as a tool to badger politicians?

I wonder!



thampan's picture


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People who adopted family planning ---- The benefits of family planning to individuals were probably accepted."Chota parivar, sukhi parivar" - Rather than appealing to people's social feelings, the program appealed to their individual benefits. The girl child campaign also helped among the educated.

i feel that the crux is individual appeal worked. 

RWH - how can we create an individual appeal ? the cost of water through RWH has to be lesser than that from govt agencies. 

average rainfall in bangalore = 859 mm (

assuming an individual house in a 1200 sqft plot - amount of water from rain = 95875 liters. Assuming 80% efficiency in storage you will get 76,700 liters of water from rain.



RKCHARI's picture

Accurate Harvestable Rinfall Quantity

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Average Rainfall in Bangalore according to the most reliable source (on whose data NASA too depends) is 909.1 mm per square metre (please see

BWSSB / BBMP is manadating RWH for homes on  2400 sq. feet and above. According to Atlantis total rainfall that can be harvested on a catchment area @ 100% efficiency is 222.967 sq. metres X 909.1 mm = 202,699.30 litres. Capacity of storage tank would therefore have to be designed for approximately 203 cubic metres.

However, in actual fact this is not true. Capacity can be designed to hold maximum monthly average of rainfall plus shortfall from monthly avarage demand. Consequently something averaging to a 60 Cubic Metre tank would suffice, presuming  there is an averagge population of 5 per household and per head demand of 150 litres per day.

In short, there is enough rainfall in Bangalore that can be scientifically collected by each household consisting of 5 members living in a sngle unit built on 2400 sq. feet of plot to last them the whole year at an average demand of 150 litres per day per head. Thereafter the household will have NIL dependence on BWSSB supplies for life! The 150 litres per head per day is inclusive of water requirements for drinking and cooking, washing vessles and utensils, bathing, flushing, gardening, car wash and miscellaneous use. This is more than NBC norms which stipulates only 135 litres per day per head.

This is not a miracle, it can actually happen where there is a will.





srkulhalli's picture

Do it yourself

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Come up with a product for residential homes which will result in zero dependency on BWSSB and it will be lapped up. Bite the bullet.

If anybody has used RWH effectively (> 75 % of water requirements), I would like to copy. Figure out how to use in your homes, govt. doesnt even need to be involved.


thampan's picture

build own operate for home RWH

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building on suhas comments,

cost of water supplied by BWSSB is given at

if there can be a company which can supply water at comparable rates through RWH, people would flock towards it immediately.

( Similar to solar hot water where the installation charges are borne by the firm and you pay per unit charges for the hot water)

tsubba's picture

the proof in puliyogre

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sort of a proof is in the puliyogre type of a thingie. but need to dig deeper.

introductory video by zenrainman. (2.45 minutes)

generally check his channel. also if anybody knows him personally kindly contact him.

thampan's picture

link from praja archives

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Tarle, agree with the puliyogare :-)

For those who cannot afford the initial setup cost or those who want to outsource the complete management, ( Malls etc), BOO products may be attractive. 


the zip file linked over there has a cost comparison for different sources of water. 

One of the incentives mentioned in the report linked above is to give a subsidy for those who have installed RWH in the BWSSB bills. 

Makes sense to me as BWSSB is anyway subsidizing our water consumption. 

Comment to RWH rules


BWSSB shall discount the water bills of those establishments that have installed RWH by ( figures to be calculated by experts).


For this to work effectively, it will require a competent authority to check RWH installations and certify them. 

sanjayv's picture

BWSSB RWH rules comments

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 General comments:

I am very disppointed both with the legislation as well as the rules.  It is quite obvious that very little thought has gone into any of this. As other pointed out, a period of 9 months is too low for existing structures. More time should be provided.  A better method would have been to first promote the concept through advertisements, public education and pother methods first while building up the expertise and infrastructure for large scale implementation.  Once that is in place, the legislation should be passed to force the hold outs to implement RWH.

Specific concerns:

(1)Time frame for implementing in existing structures. Unfortunately, the number seems baked into legislation itself.

(2) Resources for implementing the scheme.  There needs to be a major period of public education.  There needs to be effective certification programs to ensure that there are reliable contractors who can offer good quality designs

(3) Standards for the water before recharging ground water needs to be clearly specified in terms that are easily implementable,  Except for IS 10500, there is hardly any clarity on this. 

(4) Enforcement:  This is the fuzziest aspect.  I do not think the BWSSB is equipped and staffed to enforce this.  The rules also do not specify any metrics:  What percentage of the roof area must be harvested (my apt complex actually has partial RWH - do we qualify or do we need to do anything more?)  It might be better to have some willing and qualified private party or NGO to agree to certify structures.  Maybe they could require submission of these certificates by owners at the time of filing property tax next year or something like that.  Also, the way the rule is written, BWSSB is going to have to construct RWH in my property and bill me for it. What is I refuse them access  Will they come with the cops? It is also important to separate the big fish from the small fish.  Larger properties and big ticket water consumers should have a larger burden of compliance that a simple homeowner in a 60x40 site.

(5)Is ground based water harvesting compulsary - not clear at all.  

(6)How does one make this of value for new constructions?  The rules are silent about whether plan approval is required and what the negatives of not taking this are.  What if I am in a old CMC area with no piped water supply.  The threat of not providing water connection is not relevant to me.  Maybe plan approval stage is where this needs to be applied.  I hate this aspect because this is where the bribes flow.

(7)  There should also be a provision for recertification of the RWH. I ahve heard anectodal evidence of the systems stopping to work and going into disuse.

My thoughts for now.  Please continue to debate.  I will compile and send the feedback.  So disappointing that they provide one paltry week for feedback for such an important issue.  It took them several weeks to draft this tiny rules document which looks like a 2 hour job.

tsubba's picture

Chennai Media report

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Chennai's success.

tsubba's picture


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Well, Sanjay, Ram et all have pointed out that there are problems with this. But i would still like to propose use of water meters as a measure of enforcement. They should have histories for atleast past 5 years (60 months). collate them and figure out average consumption per month. then compare that with each month's consumption. that will give a good estimate of the quality of the RWH system implemented.

I again maintain, if you say, do this to improve "water table" and "greater good of the humanity and universe" and show heart rending images of ice caps melting and strandling cute little white polar bears (what happens to dark sea lions is irrelevant ofcourse)  no self respecting, anna saaru eating indian (ASaEIn) is going to be sold.  and imho, rightly so. but if you say, do it coz you will gain access to water for personal use, a whole lot of people will do it. i think we are underselling the importance of reusing water for use in secondary and tertiary purposes like washing clothes and dishes, personal cleaning, flushing toilets, gardens, etc etc etc.

for cooking and drinking it is reasonable to assume that people will still expect some guarantees and the psychological comfort of suckling taayi kaveri's teet. it is very hard to beat that psychology.

even then like they do with bio-fuels etc., BWSSB should start with a "eco" water. simple goals like 10% reused water for potable purposes. that is a very good metric to start with IMHO. that is you use 90% river water + 10% reused water. slowly as public confidence increases and BWSSB itself can establish their proficiency with technology and establish that they can reliably provide clean potable water that is recycled, then they can increase the ratios -15% -20%-30% and so on.

overnight nobody is going to acquire a taste for these scientific recipes just because of environmental concerns. the great westerners(those advanced peoples with their "superior" social attitudes) in our corner of the world, australians reeling under draught didn't do it. why would the uncivilized, evil, heathen(as in those who dont pay heed to the gospel of environmentalism) do it?

aside sanjay: what is the correct figure? i have heard 850 - 1000 mm for rains in blr. what is the a good estimate? well, on second thoughts, why bother, the range is good enough. we should assume the worst and work with it. 850 is what is good enough.

sanjayv's picture

Some other docs for reference

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 Please see the following documents of the TN govt's.  They are calling that "Government Orders".  Is it the same as our rules and regulations?

Please see a copy of those documents here. Chari sir, there are some sections of these docs you will love.  It talks about storm water drain design such that there is maximum percolation of water into the round.  I LOVE the level of detail spelt out in the document.  How can we get someone from TN to discuss their policy ideas and what worked and what not?  I would love to hear that discussion.

From my reading, the TN govt rightly perceived that publicity is required to get people to see the benefits of RWH (to themselves). The TWAD (Tamilnadu Water and Drainage Board) actually started publicising RWH from 2001 (based on news items in the Hindu).  Why can't we learn from these success stories and adapt policies instead of doing what, in my personal opinion, is a junky approach.

RKCHARI's picture


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Thanks Sanjayv for the link to Tamil Nadu Rules on RWH.

Wonder why Karnataka is not blindly following this well thought out document with relevant modifications?

I would also like to draw attention to last page article in the latest Business India magazine where they have reported an interview with Water Resources Minister in the Union Cabinet - Mr. Bansal. Apparently Central Government gives quite a few subsidies to State Government to implement RWH in each State mandatorily.

Publicity is the most essential tool to convince people that out of 135 litres per day, per head mandated by National Builders Association, as much as 130 litres can be used by re-using treated water including RW harvesting. Per head, on an average we do not drink more than 2 litres and cook in more than 3 litres per day. So apart from consumption through human ingestion, for every other use we can use recycled / treated and harvested water.

I hope these do not end up being merely empty dreams!




zenrainman's picture

Rainwater harvesting rules

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 Good feedback, will carry ALL the messages to the committee.

A couple of quick clarifications

The rules of ALL other states have been studied, deliberated and then this notification.

This rule itself is not cast in stone, the idea is to start the implementation and then see issues emerging and to fine tune it for the 'public good'. 

Please note what has been sought to be prescribed is a 'minimum' , people are free to take it 100 % harvesting if they so choose to. Making zero runoff compulsory will simply be a very huge cost. 

Rainfall data has been studied for over 4 sites in Bangalore. Rainfall varies by as much as 15 % between the 4 measuring stations with the highest being reported at the Central station of IMD near the Maharani's Science college.The 20 mm rule is to capture at least 50 % of the rain spread over nearly 60 rains. 

The nature of the institution determines the law i.e in Tamil Nadu the Govt department notification applied to all buildings in T.N both urban and rural. Here the notification is by the BWSSB which can influence only the places where it gives a connection. Stormwater harvesting in drains, parks ,open spaces, roads etc would be with the BBMP not the BWSSB. 

Grey water recycling and black water reuse are outside the purview of the rainwater harvesting bye-laws now introduced.

As regards comparison with Chennai, the committee has visited Chennai and has had extensive discussions with all concerned .

If people are interested , they can visit the website, download the rainwater calculator , punch in their roof area , daily water demand and storage capacity in the Excel sheet and they will get an idea of how much water can be harvested with a 20mm rule or otherwise.

The idea in so far as I could get is not based on punitive actions but on convincing the citizenry of Bangalore of the benefits and therefore rolling it out at city scale.

...and finally for Mr Chari, yes indeed I have visit many countries and the unique question I ask people is about how they harvest rain . Especially in Australia the answers have been very, very interesting.

Let us all do our bit , spread the word see the difference that it makes to our cities.

These views are of course personal...

RKCHARI's picture

Thanks for Clarifications

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Thanks Dr. Vishwanath for the clarifications on various points rainsed by Prajagalus. Thanks also for confirming your having actually seen what happens vis a vis RWH in other countries - particularly Australia. I hope the experiences were pleasant.

While I am aware that you believe they do an overkill, I strongly feel unless you benchmark at the highest level, we wont even reach midway. And not as if cost-wise aiming for the best is going to be too expensive. You will be glad to know over the last two years I have managed to hammer down Atlantis prices to a fairly reasonable level. So much so that we now promote them as solution providers and not sellers of plastic goods useable in RWH systems!

TWAD is a State body while BWSSB is only for Bangalore - that one is aware of. However, reading Tamil Nadu rules and drawing microcosmic regulations based on similar rules for Bangalore need not necessarily be discarded out of hand. I am sure with you on the Committee you will ensure the best rules are framed. My humble advice - kindly do ask for the moon and you will at least get a 100 Watt bulb of illumination, if I can use that as an analogy!

Warm regards,



zenrainman's picture

Rainwater harvesting rules

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 I wish I was  Dr. but am not , so plain old Vishwanath will do :):)

Rules have to be implementable , have broad social consensus, should translate into seeable benefits and should have the simplicity to be understood and implemented quickly.

The challenges are

1. How do you create the trained and skilled workforce which will understand and implement the rule quickly

2. How do you ensure that this not turn into a rent seeking behaviour.

3. How to develop the nascent Indian products market for rainwater harvesting - just like the solar water heating market.

4. How to highlight good examples and facilitate easy access to designs and implementation skills by people who want it


A guide book will follow in Kannada and English very soon. Training of plumbers will begin and this will be handson ...

The water situation in Bangalore needs many an intervention of which rainwater harvesting is a component ...hough important. 

Unless we create a institutional and legal framework for easy management of groundwater the benefits of recharge will not flow easily. That too remains a challenge.

PS One could also ask for the moon , since there is water there perhaps?? :):)  but one is right now asking for the clouds.....this is an interlinking project between the sky and the earth ... much better than the rivers one.... 





tsubba's picture

zen and the art of rainwater harvesting

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thats some serious low down ZRM. thanks.

one of the things is that the overall water situation in blr is not the same as in chennai. for example the number of manmade and natural lakes is different. ultimately even for water tables, apart from things like flooding, i am guessing it is very crucial to revive the natural valleys or get the waters flowing like they used to. am i right?

s_yajaman's picture

Ranifall statistics for Bangalore 2000-2009

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Here are rainfall statistics for Bangalore from the Hindu archives.  A bit more helpful than the 909 mm annual average.  The only guess was for Mar-May 2003 when I could not find data.


Jan-Feb Mar-May Jun-Sep Oct-Dec Total
2000 0 132 675 333 1140
2001 0 386 467 198 1051
2002 0 189 358 217 764
2003 0 150 394 215 759
2004 0 260 699 179 1138
2005 0 249 673 675 1597
2006 0 289 297 92 678
2007 0 253 747 234 1234
2008 20 157 850 261 1288
2009 0 220 704   924
Average   229 586 267 1057

March to June is the time when the water crunch is in full swing in Bangalore.   And we get about 23 cm or 0.2m of water.  A 240 sqm site would be able to harvest 48m3 of water @ 100% efficiency or about 25m3 water at half that.  25000 l of water is 250 l of water a day availability (over the 3 months) - which is pretty good. 

What should we design the tank for?  If all this water fell on Mar 1 and nothing ever fell again we need a 25000 l tank.  But that would be unlikely.  It would also not fall very uniformly. 

We can plan for a peak rainfall of 10cm or about 12000 litres tank capacity. 

The rest can recharge ground water?

Hope this helps.




Drive safe.  It is not just the car maker which can recall its product.

sanjayv's picture

Revised critique of BWSSB rules

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Dear zenrainman sir,  thanks for your inout on the existing rules and the process for formulating the BWSSB rules.  SInce you will be carrying the feedback here to BWSSB, I am not going to send anything separately.

I still think (a) the rules have to be more clear (b) provide sufficient definition for any dispute resolution in the future. A citizen reading the rules should have no doubts on the general frame work.  From that perspective, here are some comments.

Disclaimer:  I am just typing in everything that occurs to me.  Have no expertise in domestic plumbing or the rules and regulations. So please ignore any stupid statements.

The objective of the BWSSB rain water harvesting rules should be to lay the framework for the implementation of the law passed by the legislature.  The objective of the rules would be to translate the intent of the legislature to an implementable frame work.

The law requires that every owner or occupier of a building (of any kind) having a sital area of 2400 square feet or above or every owner who proposes to construct a building on a sital area of 1200 square feet and above shall provide for rain water harvesting structures as provided in the regulations.  If the said structure is not provided, the BWSSB has the authority to provide such a structure and recover the costs from the home owner or occupier, as the case may be, as arrears of land revenue.

This amendment has been inserted as section 72A, after section 72 which stipulates that sewage and rain water drains are to be distinct

So, some clarifications are required here: 

(1)    The law provides for those already having a building and those proposing to construct a building.  Does this cover those currently constructing buildings? Which category would they come under, the existing (2400 sq ft) or proposing to construct (1200 square foot)?  Legally, what document would decide whether a building is proposed or existing – plan approval, occupancy certificate?

(2)    Currently, as the BWSSB does not really supply water  and provide sewerage facilities to all buildings within its jurisdiction, especially in the newly added BBMP areas, does this rule apply to those buildings also. As the BWSSB starts providing supply will they start requiring RWH to new customers? What sital area standard will be applied then to existing buildings?

(3)    In case of existing buildings, the onus has been put on owners OR occupiers.  So someone renting the building is liable to erect a rain water harvesting structure? However, since they do not own the building, or the site, the penalty as described below is not binding on them.

(4)    The penalty will be assessed through the revenue department as land arrears … this is a little bit of a gray area.  If there are buildings where some dispute is ongoing in land arrears and this amount then could become non-recoverable to the board until that dispute is settled.

Okay, now if I am a site owner

(1)    I need to get a RWH system installed in 9 months time.  Since this is an amendment to the BWSSB act, I have to use a licensed plumber according to section 59 of BWSSB act.  How do I know if my local or old licensed plumber is trained in RWH good practices?  What if I am a bigger setup and use a contractor? What licenses apply?  It would be good if the rules would call this out.

(2)    Section 4(a) of the rules say that the water should be used for non-potable purposes.  So does this mean that houses with RWH have to have dual plumbing and dual overhead tanks (potable vs non potable) ?

(3)    Section 4(d), design criteria says that storage tanks or recharge structures should have a provision of 20 liters or more per square meter of roof area.  Should the recharge provision not talk about some kind of rate (20 liters per hour per square meter of roof area or something?)  Also, any recharge provision should be for the maximum rate of rain expected… otherwise there could be some internal flooding potential?

(4)    What about homes that (maybe in violation of setback requirements) have limited space, no borewell or open well.  (I know examples of such places existing).  For someone on a 40x30 site, it is worth thinking as to how challenging these requirements are.

(5)    I strongly feel that the rules should clearly specify a percentage of roof area to be harvested.  Otherwise, someone will connect a gutter to a well and try to get away with it.

(6)    Item 4(b) has a typo – last 2 words should read open well and not bore well.

(7)    Some kind of standards for the plumbing, treatment and water quality requirements before ground water recharge as well as filteration requirements should be listed here.  I think it is part of the overall specification that will help if there are any disputes between the plumbing contractor and the building owner.

From a new building construction perspective – someone with a 1200 sft site is going to be really challenged to find space.  The procedure for getting the RWH design ratified should be made clear. Otherwise it just makes it easy to get harassed by everybody who has to give a permit or clearance.



sanjayv's picture

Some thoughts on the 4 questions raised

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 1. How do you create the trained and skilled workforce which will understand and implement the rule quickly

This is indeed a major challenge.  The BWSSB act only requires that a,licensed plumber be used.  I think the RWH rules and regulations should clarify that training is required.  The BWSSB is going to have to figure out a method to train and certify additional plumbers.  Scaling this to the extent required is going to be hard.  Is there an estimate on how many would be required?  The 9 month rule is also a major issue. 

2. How do you ensure that this not turn into a rent seeking behaviour.

No ideas here.  My biggest concern is the quality check, enforcement and long term maintanence aspects.

3. How to develop the nascent Indian products market for rainwater harvesting - just like the solar water heating market.

The solar water heating market has just adapted a lot of technologies available worldwide.  Suitable govt policies appear to have spurred their use. (I qualify as an expert on solar heating technologies).  RWH technologies can easily develop - should not be a hard area to develop solutions for.  The problem in our country is anything innovative will be copied and replicated without the innovator making any money.  So incentive is limited. The other big problem is standardization. For example, some connections which should easily mate and be leak proof in theory  just do not sometimes.

4. How to highlight good examples and facilitate easy access to designs and implementation skills by people who want it

I think this is the easy part - with a moderate budget.  Several ideas in no particular order.  Need not all be practical.

  1. One example will be something like the Chennai RWH house where several examples are shown.
  2. Require every house which completes a RWH installation to get certified and display a board/sticker - "This house harvests rainwater" System installed by xxx. Certificate number.
  3. Organize events - one idea - a tour of rain water harvesting homes in neighborhoods througout the city.  (for an analogy, please see this "Tour of solar homes" in the US. I started one of these in the town I used to stay in several years ago.  The even is still going strong there and is very popular. It lets people see actual installations and talk to homeowners about their experience.
  4. Issue regular press releases with the ground water level in several example wells around the city.  I grew up in Chennai and the water level in the 3 major water reservoirs (Red Hills, Poondi and Sholavaram) were reported every day in the paper.  It helped the public get a feel for the water situation. Showing the improvement due to RWH will lead to a feel good factor.
  5. Have contests - say for the best RWH implementation, by ward / neighborhood, region of the city etc.  The contest can be designed several ways and the prize can also be very imaginatively conceived and announced.  Put out the prize winning RWH homes as case studies in local papers, magazines, TV etc. discussing implementation, choices, costs, who installed it etc.I Get some big personality to give the prizes.

In short, where there is a will and some amount of budget, this part can be easily done with solid impact.


sanjayv's picture

RWH updates

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 Summary from a few news paper articles.

TOI article

  • There was a RWH session in RT Nagar recently.
  • BWSSB plans to give a prize of Rs 10,000/- for 5 houses that implement RWH in Jan 2010 (on what basis, not clear). 

DH article on Hasiru Santhe

  • RWH will be promoted among other things at a Hasiru Santhe being organized at Sankey Tank Park on Sundar morning (Oct 25th).

RWH Workshop

  • A awareness workshop on RWH will be organized "shortly". Contact PRO on 22945114 if interested
  • Some 4 lakh pamphlets both in English and Kannada are being distributed by meter readers door to door.

Politicians show the way

  • RWH structures have been installed in the CMs various residences - "home office" Krishna, "official residence", Anugraha on  and "home" on Crescent road.  Other homes fitted with RWH include that of the speaker, cief secretary and opposition leader. Karnataka State Council for Science and Technology did the design and BWSSB installed.  Installation consts ranged between Rs 24,000/- and Rs 1,00,000/-. Holy cow!

More BWSSB law amendments in the works

This is fairly complicated.  I wish the law goes through a public review perid for suggestions before being introduced in the legislature,  The water sector needs much more reform. comment guidelines

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