RainwaterToilet

Projects
Participants
Skills	Plumbing, Building
Status	Active
Niche	Mechanics
Purpose	World domination

To try make my new house a bit more environmentally-innocuous I decided to make a system that collects rainwater and uses it for flushing toilet(s), in addition to irrigate the garden.

First I had to make a design. Several systems are possible, but for simplicity I opted for a pressurized water pump (hydrofoor) that simply automatically keeps its outlet pressurized. Then you can make the rest of the system like any other standard plumbing, since the municipal water supply has similar properties. A lot less error-prone than remote water-level sensors that need to signal a pump to shut off...

So the requirements were:

• a large buffer (rain barrel) plus automatic fill system
• pressurized water pump + water filter
• a separate extra conduit from pump to toilet(s)
• re-routing some of the roof drainpipe to collect as much water as possible
• a system that allows switching back to tap water in times of drought

I purchased a beautiful 400 liter rain barrel that is very discrete. The cheapest pump I could find https://www.ts24.nl//product_info.php/info/118962/Eurom-Hydrofoorpomp-FLOW-HG-800P/

To try make my new house a bit more environmentally-innocuous I decided to make a system that collects rainwater and uses it for flushing toilet(s), in addition to irrigate the garden.

First I had to make a design. Several systems are possible, but for simplicity I opted for a pressurized water pump (hydrofoor) that simply automatically keeps its outlet pressurized. Then you can make the rest of the system like any other standard plumbing, since the municipal water supply has similar properties. A lot less error-prone than remote water-level sensors that need to signal a pump to shut off...

So the requirements were:

• a large buffer (rain barrel) plus automatic fill system
• pressurized water pump + water filter
• a separate extra conduit from pump to toilet(s)
• re-routing some of the roof drainpipe to collect as much water as possible
• a system that allows switching back to tap water in times of drought

I also needed to determine a suitable spot. Putting it outside means you have to shut it down and drain it in times of frost. Putting components inside can cause noise problems, and takes up a hell of a lot of space. I decided that outside the house was the best choice.

I purchased the cheapest pump I could find, some tubing and fittings, two water filters, a check valve, a dry-run protection sensor and built a proof of concept. All told between €250 and €300 I think. Then I put the assembly in my work shed and also purchased a beautiful 400 liter very inconspicuous rain barrel. Digging a large hole in the garden to put in a 1000l underground tank was way too much effort.

Stuff I learned along the way :\

Don't save on tubing and fittings. Instead of getting the good 1" tubing (reinforced, otherwise it 'collapses' when the pump starts sucking water!) I went with the cheaper variety. The trouble with that is that the clamps cannot "grip" the tubing well enough so you never get a 100% tight fit. That resulted not just in tiny leaks, but worse it lead to the pump losing pressure overnight so it had to be reset every morning. There was a mismatch between the clamps and the tubing, or it was the wrong tubing.

Getting a conduit all the way through the outer wall, past the kitchen, all the way to the front of the house is a gargantuan task, depending on how your house is laid out, your willingness or ability to demolish stuff, and other factors. Had the bathroom been at the other side of the house it would have been so much easier... oh well, gotta do what's gotta be done.