Lawn sprinkler using rain water and sump water

Old 07-24-07, 08:53 AM
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Lawn sprinkler using rain water and sump water

I just bought a house that has an inground sprinkler system with 4 zones. Currently the system runs off of city water. I would like to change this for several reason, watering restrictions, water bill as well I read that city water is not good for your grass.

I was thinking of putting in a water storage system that collects rain water from the roof as well as sump pump water. The system would consist of a storage tank (above or in ground), a pump to run the sprinklers, some sort of float switch connected to city water that will ensure a minumum water level in the storage so the system can run even if all reclaimed water is used.

My question is if this is fesable, what size of storage tank would I need to hold at least one lawn watering in it, preferable more?

Also any other suggestions or opinions would be appreciated.

The total lot size is 6000 sq.ft with a 1000 sqft taken by the house (2000 sqft / 2 story) as well as a 2 car garage and driveway, deck etc. I will not have a better idea as to size until I take possession.
Old 07-24-07, 10:30 AM
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Lawn sprinkler using rain water and sump water

If you can collect the water from 1500 sf (house plus garage), 1" of rain will be 125 cubic feet.

If you water the equivalent of 1" on a yard area of 4000 sf, you will need about 300 cubic feet of water.

Assuuming you can collect all the water on the roof, you would need about 2.4 inches (300/125) of rain to equal adding 1" to your lawn (which you may not need until well after you have had the 2.4 previous 2.4" - Everything will depend on your rainfall and how much water your lawn needs (soil type, absorption and evaporation). Once you get the exact yard and roof measurements, you can adjust these numbers a bit. - A couple of concrete septic tanks might be one stroage method.

Your supply from a sump pump wil depend on the whether your sump runs fairly frequenly or only when you have a big rain. If it only runs when it rains, it will not do much good since the grass does not need water then.

You may want to look into two other options.

1. If your city includes sewerage treatment in the cost of water, you may be able to install a dedicated meter for watering that runs at a lower rate. This is done in some cities.

2. If the ground water is shallow you may be able to drive a shallow well that you can fill/top off the storage tank if rain is infequent.

Good luck


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