I would like to convert my current rain gutter system into a collection and recycling process. Currently the water is just runoff and ends up in the storm sewer creating more work for my cities aging and already overburdened infrastructure.

Is there a way that I can collect this water, filter it naturally, and recycle the water in a sustainable way?

  • The following sites may contain the answer you are looking for: Potable Rainwater, Filtration and Purification and How to Install an Eco-Friendly Water Filter System
    – Linger
    Feb 6, 2013 at 21:10
  • I think your second link is close to what I am looking for but I think it leaves out some important parts. The first link seems not to be sustainable.
    – user141
    Feb 6, 2013 at 21:30
  • Please edit your question and describe how your house is constructed and what your neighbourhood looks like. The available options depend very much on this. It makes quite a difference if you live in a row of houses in a city or in a standalone building in the countryside.
    – user2451
    Feb 29, 2016 at 14:28

5 Answers 5


A detailed answer is probably beyond the scope of Stack Exchange, but here's an introduction:

The hard thing about collecting rainwater from your gutters is that it gets dirty when it hits your roof. If you have a metal, slate, or clay roof it's cleaner than roofs based on oil products, but it still needs cleaning before drinking.

The easiest approach is to use that water for other purposes - watering the garden, washing clothes, even bathing, and continue to use fresh tap water for drinking. Using a Humanure system will further reduce the amount of fresh water you use.

A very sustainable approach to purifying rainwater is a slow sand filter. It's a simple technology, using easy-to-obtain elements (a barrel, sand, etc.), and anyone can set one up. They do require regular attention and maintenance. Here's one site to get you started: http://www.shared-source-initiative.com/biosand_filter/complete_biosand.html

Storing water is also going to be an issue: in most places there are wet seasons and dry seasons. If you want to save water for the dry season, you're going to have to find a place to put a large container.

Good luck, and consider blogging what you do.

  • 5
    Also, the biggest cost to benefit ratio device you can add is a First Flush Diverter these, as the name implies, will divert the first few liters/gallons of water from your roof AWAY from your water supply. The theory is that those few gallons will wash away the dirt that accumulated on your roof between rains.
    – Aron
    May 26, 2014 at 15:22

on my homestead we save the rainwater in a cistern then filter it with a reverse osmosis filter powered by a solar panel. Its worked pretty well for three years. I know we'll have to replace the membrane every so many years, but thats pretty low waste. I'd call that sustainable.

  • This is a good option but you have two issues. firstly; you must consider the storage of the water after it is filtered because without chemicals like chlorine it can become infected with bacteria. And secondly; depending on the filter, reverse osmosis can strip water of all it's minerals making it TOO clean - so you would need to add backthe salts and minerals that are essential to life. Too much pure water (I mean PURE - would result in the breakdown of the nervous system if vital salts are not replaced.
    – user20110
    Aug 12, 2016 at 20:56

I shared a google slide presentation an calculator on Rainwater Harvesting. It's an intro course. I hope you'll find helpful.

Be sure to check out the collection/storage/use sizing chart slide. Calculator is also here in case the url isn't working in the sizing slide linked above.

Tips Use at least one first flush diverter. The idea is to collect the cleanest water possible before storage. Then you want to "use" the cleanest water from the tank. So build a floating intake yourself. Bad for gravity use but good for quality. I use gravity for a backup distribution system so I flow from the bottom of the tank.

If you don't want to risk getting sick, consider a 9 and 3 micron dual-stage filter with uv light. Use large, sturdy screen at the in and out flow of the tank to keep critters out. Chlorine at 1 part per million will kill pretty much everything and I think most instructors recommend some combination of all this stuff.

I recommend using everything. Especially if you use pesticides that could be ingested by critters. When they get sick, they look for clean water supplies.

Feelin' lucky? Get a part per million meter to gauge how close to "perfect water" you can get. Get a ph meter to gauge the acidity of the water. Radiation?

Addendum for the pluviophiles (lovers of rain): I live about 7 miles from an active volcano. My metal roof flows into plastic gutters and pvc pipe is used to convey the water to my food-grade holding tank. It has crud on the bottom ie; life.

My water has a slight yellow tinge from the Ohia tree leaves that collect in the gutter. I give the water a bunch of positive intention, specifically love and gratitude and the color will change, sometimes.

I use a first and a second flush diverter. I don't use filters and do very little mainteance on the system. I have a close connection with the water.

Ultimately, I believe the connection you develop with your water is a big health factor. It's worked well for the during the last 5 years.

Some folks see rainwater harvesting as owning their own water supply. I see it as a gift to be able to attract from the sky, one of the things I need most. I REALLY love my water. It's the only water that quenches my thirst. Bottle water makes me thirsty, tap water smells and tastes too much like chlorine and eh, I forgot what else I had to add. Did I miss anything?

Also watch the "Rainwater Harvesting TED Talk"

Ka Wai O Kane!
(the water of Kane, or rainwater)

  • Can you please edit your post? That first link is not to a tutorial but to the Google spreadsheet calculator. And please don't use URL shortened links. A link to that TED talk would be nice too.
    – user2451
    Jul 24, 2016 at 11:04

People have been drinking untreated rain water for centuries.

In our home, we use simple filter cartridges which we change annually.

My only advice would be to consider your location. If you live near a volcano or industrial areas spewing our pollutants into the air, then reverse osmosis is probably the safest solution.

If you live in the country, then drink it just as nature supplies it.

  • 3
    People throughout the history (their digestion system) were used to the untreated water (which was not spoiled by today's pollutants). Even today there are countries where people drink naturally supplied water because of necessity. If you're not used to this, it could cause serious problems. But there could be some ways how to "naturalise" your digestion though.
    – Peter Ivan
    May 3, 2013 at 6:27
  • 3
    @JasonPascoe - I think that suggesting that people should just drink untreated rainwater as a blanket statement is dangerous. In my situation I have a tar based roof, in an area with quite a bit of heavy industry. Not to mention the poisons that my neighbors and area spray to kill insects and weeds that end up in the rain barrel. So while in theory I agree the ability to do that safely ended with the industrial revolution.
    – user141
    May 3, 2013 at 12:55
  • 3
    As I said above "My only advice would be to consider your location. If you live near a volcano or industrial areas spewing our pollutants into the air, then reverse osmosis is probably the safest solution." I live in the country with the nearest industry 100kms away and my roof is made from colorbond, which is like a waterproof coated steel. May 3, 2013 at 15:11
  • 1
    By definition most people live in heavily populated areas, which is where the pollution is. People have been lucky to live 50 years until very recently, the problems they faced were very different to mine.
    – Móż
    Jul 25, 2016 at 6:44

I am saving rainwater for a long time to water plants in garden. I got a plastic tank with 1000 liter capacity. Last year I brought a TDS meter (Total Dissolved Solids) and it shows that the tap water has a reading of 874 mg/L, bottled water has 83-85 mg/L, and rain water only 16 mg/L. That's amazing.

So I just thought brought a new Reverse Osmosis (RO) filter to filter this 1000 liter water and I got a very clean 4-7 mg/L for the TDS. Its taste is great but when I tried to drink this water it made me sit in the washroom all day.

  • Welcome to Sustainability.SE! If you are new to Stack Exchange we recommend taking the tour first to get familiar with how everything works.
    – THelper
    Jul 23, 2016 at 17:23
  • 3
    I have edited your question to explain some jargon you were using and added units to your numbers. But after that, it still does not really answer the question - you are just telling the OP what not to do based on one 'measurement'.
    – user2451
    Jul 23, 2016 at 19:08

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