Rainwater collection to supplement public water

Has anyone experimented with catching rainwater and hooking it up to your main water supply? I have public water and I would like to know any details there are on capturing rainwater, filtering it and then using it to supplement public water. Since I have zero water pressure, I use a pump to get the pressure needed for a 2 story house. I have a 55 gallon holding tank so the pump sucks in enough volume, so I could see that being an important part of the collection system. Any ideas or experience are welcome. Cheers!

I know you wrote quite a while ago, but I wanted to share my experience, though we've ended up not using rainwater for our home. We planned on using rainwater, collected in a 5000L water tank, for all our household needs excluding drinking.

We discovered quite late in our building that the challenge came with also using solar power. Our solar panels provide enough energy for household use, but the inverter can only handle about a 1000W surge. The problem was that all pumps (available in South African, at least) used a lot of power on startup. So for now we're using city water, and the rainwater is for use in our garden and food forest.

Our pressure is also very low because we set up a low-pressure solar geyser on our roof. The thing is, for a family of 5 we really don't use that much water with a low pressure system and no toilet. Less than a kL/month. It turns out that flushing a toilet really used a lot of water (we have a composting toilet now)! We were using about 7kL/month in our old house, with a family of 4, down to 1kL now, for a family of 5. I guess a hand pump to a roof holding tank might be completely doable, but not something we have had access to, just yet.

I envy your 5,000L tank.

Because of our prolonged drought I decided to collect rainwater in earnest this winter (our rainy season). We have enough city water for the house and cooking, but conservation and gray water use are definitely being enacted.

For rainwater collection, I use a primitive system. I have amended the 4 house downspouts and those are directed into trash cans and other containers. No fancy plumbing involved, but then the water wont' be filtered since it's just for use in the garden. I also have obtained a couple kiddie pools that will hold about 500 gallons each. And a few other storage techniques. I should be able to store about 3,000 gallons to be used in the garden in the dry summer months. The largest problem with my system is preventing as much evaporation as possible. I move the water around with submersible pond pumps attached to hoses (GFI outlet) which works better than expected.

The amount of rain that can be collected is amazing. It takes about 0.1 inch on the roof to get things flowing. From there, one can collect approximately 600 gallons for each 1,000 sq feet of roof - per inch. Or so I've read.

Rob Sigg wrote:Has anyone experimented with catching rainwater and hooking it up to your main water supply? I have public water and I would like to know any details there are on capturing rainwater, filtering it and then using it to supplement public water. Since I have zero water pressure, I use a pump to get the pressure needed for a 2 story house. I have a 55 gallon holding tank so the pump sucks in enough volume, so I could see that being an important part of the collection system. Any ideas or experience are welcome. Cheers!

This reply is certainly very belated but everyone who has rainfall already has a solar pump at work for them! All you have to do is harness it!  Everyone who has a house/barn/shed with an eaves trough/gutter has an excellent abs or pvc pipes from your roof to your tanks (it doesn't matter how far the tanks are from your roof, the sun will pump the water into them by gravity.  I have 6 such drums fed by 2 downspouts and the water I collect waters our garden so I don't have to pay to pump water from our well to do that. I'll try to put pics of this here in a few days.

Here's some pics of my solar powered water collection system. One downspout from a one storey roof and one from a two storey roof. Storage is in 6 steel drums located on a framework just below the level of the eaves trough so gravity fills the whole system.

Has anyone built a house where code does not allow gray water but built in such a way that after inspection, it is possible to revert to a dual system with fresh water (well or city) and gray water (rain water)? I envision a system that takes gray water and rain water for use in toilets or on gardens and such. Fresh water would be for human consumption. We will be required to have a septic system at the outset so that would be the destination for the sewage but all else would go into the gray water cistern or duck pond.

Any experience or advice on this type of set up would be welcome.

Thanks

It is strongly advised not to store grey water in any kind of tank, because it turns to black water.  Rain water (not mixed with grey water) can be safely stored in tanks.  http://oasisdesign.net/greywater/

We have a septic system but I replumbed the laundry outlet to discharge into a basin for eventually irrigation of trees.

Grey water goes directly into the garden without a tank and after the inspection...
For the rainwater you need a pump which is called water switch, that means that the town water automatically clocks in when the tanks runs empty (at least this is the high tech version).

Thanks. I should have read what I wrote...wasn't clear. I have heard of systems where gray water supplied toilets but I may be mistaken.

The concept I am pursuing is dual supply and dual output. Supply would be well water for sanitary/human consumption and rain water for toilets and non-sanitary uses via a cistern (I thought gray water might possibly be used to supply toilets but if it can't be sequestered, then no).  

The output of the system would be sewage to a septic system and gray water emptying into a duck pond with fish and aquatic plants to clean. Duck pond supplies garden with irrigation. Anyway, yes, gray water to the garden via duck pond.

The question should have been how to set up the plumbing to pass code but be easily converted to a set up that segregates the gray water out from the sewage and allows the supply to come from two sources as well.

Sorry wasn't well written (distracted by work)

Art Ludwig is considered a (if not the) grey water guru.  His book may help you if you can't get enough info from his site:  http://oasisdesign.net/greywater/buildersguide/

Someone who used to work in public works warned me against this, I guess okay for get water, not drinking into plumbing. Apparently there are additives to our city water that helps lead not leach into it from all the old pipes. Then, of course, there's rain water cleanliness given bird poop on the roof, etc. With the right piping, cleaning, etc. it's probably a good idea for anyone to have. For using in the garden, organic matter is a better storage container than barrels, I think. Though, I plan on having 3 rain barrels myself.

Godfrey Wilson wrote:I have heard of systems where gray water supplied toilets but I may be mistaken.

I think probably what you've heard of was people saying "I'm planning a system to store my greywater and pipe it to flush toilets, isn't that great?" but what you haven't heard of is people saying "I've been piping my greywater to flush toilets for the past 5 years and it works great!"

Rain water is fine for flushing toilets. My sister in California and her architect husband have over the years installed systems that save a lot of water for them. Their greywater from showers and baths goes to irrigation in their own yard. They have a rainwater tank under the deck, that flushes toilets.

Art Ludwig's book is great if you are thinking of using greywater. He points out that in practical experience, filtering and storing greywater isn't effective. The most effective way to use greywater is to get it out into topsoil or mulch basins as soon as possible, where the aerobic organisms can use the nutrients and moisture quickly.

We have a system whith  a tank and town water. The tank is plumbed inside but if it is empty we get town water. It tastes terrible (the town water). I would like to have an extra tank maybe stainless steel a small one for drinking water only. The setup was done by a plumber but you probably can do it yourself. There are these plastic connecters (plasen or so) very easy to use.

i have been using rain water for years to flush the toilet, cook, shower, and drink. During the warm months only i live in a climate where shit freezes. I have a tank on my roof that fills from the gutters from the roof above it and 2 tanks on the ground that fill from the rest of the rooves. i have a 1 gallon minute sprayer pump to transfer the water from the lower tanks to the roof tank. all on one manual switch so i have to watch to make sure the lower tanks dont run dry or i overfill the roof tank.

i am currently building a second use water system for flushing the toilet at my moms house it is fed from the washing machine discharge.

Have a look at this topic
Benefits of rainfall collection