Rain water pump question

[Jack 07]

My game plan is to set up a rain water tank and use a pump to wash cars etc. (So far not illegal to do here). My question is, what type of pump? I want it to come on when the hose is open and off when not. Is that an "on demand" pump? Or can I have a pump run when the hose is closed? Anyone do something like this and can provide some guidance?

reasoning is we have very hard water and very nice cars.

 

[1953mercury]

You just need a standard pressure switch on the outlet side of the pump. Available at the hardware store or plumbing supply. A pressure tank would keep your pump from running constantly. Mike

 

[Leaflessshadetree]

Gas or Electric?
When running a pump needs to have water flowing through it for cooling. This can be accomplished by simply teeing off a second hose and routing it back to the tank.

I'd probably get something like this:
http://m.powerequipment.honda.com/pumps/models/wx10

 

[The Cobbler]

1/2 HP Shallow Well Jet Pump with an expansion tank will probably cost you under $200

 

[Nowater]

That's a lot to do to wash your own cars. Are you washing someone else's? If so there may be requirements as to what are you planning to do with the runoff from washing the cars. Check first.

 

[Jack 07]

Nope just washing mine, but I do it a lot. And in looking at the propane tank where the sprinklers hit it, it is brown with rust. Don't want that on the cars. There is a osmosis system you can buy, but that is $$$.

 

[HeelSpur]

You probably want something like this for just washing cars.

 

[Bear]

Or if you have a 12 power supply (think car battery) you could just use an RV water pump. Light, reasonable cost & on demand.

 

[HOTFR8]

Take into consideration if you intend to run a pressure washer. I have a small electric pump and just plug it into a power point as I use it. I have snap on hose fittings on each end bigger fitting on the inlet so as not to get confused. Turn on the water and turn on the pump (never let it run dry) and away you go.

I have a rain water tank here just for the purpose of vehicle washing as it is much better than the town water.

If you use it carefully you do not need a pressure switch like the one in the photo. If you intend to make it a permanent fitting and plumb it then use a pressure switch.