View Full Version : water lawn from lake

03-27-2007, 07:39 PM
Do you guys think it is cheaper to pay for water to water your lawn, or cheaper to pay the electicity to run an electric pump to siphon water from a nearby lake to water the lawn? I'm not asking for any negative comments here, just the facts.
I suppose I could do the math to figure it out, based on the power used by the pump for x amount of time, versus how much I would pay for x gallons of water, but wondered if anyone knew offhand?

03-27-2007, 08:27 PM
Figure ten to one, or even more, for comparing city water cost versus pumped lake water.

Bob NH
03-27-2007, 09:11 PM
After you decide how much water you will be using, you might run your system by here for suggestions before you buy the hardware. It is easier to get the right stuff to start with than to try to make a mismatched system work.

03-28-2007, 04:13 PM
I was thinking I could plug the pump into one of those electronic timers that you can set (i already have an outdoor one). So basically, the timer would turn the electricity on to the pump, which would then start pumping water to I'd say about 3 sprinklers. I'd probably run them around 2-3 times a day for 20 minutes.
The only thing I am uncertain of is whether or not the pump would need primed every time it starts up? If that's the case then this is useless to pursue.

03-28-2007, 05:58 PM
So far as I know, there are no irrigation controllers you can plug a pump into. Your location figures into these answers, so please tell us what state you live in.

03-28-2007, 06:32 PM
Live Virginia. I was going to hook up the pump directly to lawn sprinklers. I'd probably run a 1" line in the lake, and then have it tee off into maybe three sprinklers.

Bob NH
03-28-2007, 07:07 PM
You can plug the pump into a timer but you need to be sure the timer will handle the load. If you need more load capacity than the timer will handle, you can use the timer to operate a relay. If you are using standard AC power, you can use a relay with a 120 Volt coil such as Grainger stock No 5YR16 which will handle 1/2 HP at 120 Volts or 1 HP at 240 Volts.

If you are using a controller that has 24 VAC output signals:
Depending on the horsepower of your pump, you can get a relay that will fit in a small box near your controller. That relay can be actuated by the 24 Volt circuit on your controller. Grainger Stock No 5YR19 has a 24 VAC coil that will work with your controller and will operate a 1 HP pump at 240 Volts.

There is often a "Pump" contact on the controller. Connect that contact to power the coil of the relay and the pump will start when the irrigation system opens the valves. If you have only one zone, you don't need valves. You can just hook your hoses to a manifold on the discharge of the pump.

Since you will be using the pump lightly, I suggest a jet pump, 1/2 or 3/4 HP, and let it run without a pressure switch or tank. Match your sprinklers to the pump so it will operate in the range of 40 to 60 psi.

If you put a foot valve on the line into the lake, it will not lose prime.

You should install the pump at the lowest elevation possible, close to the lake.

03-28-2007, 07:10 PM
Virginia lets you out of the sort of equipment used in never-freezes Florida. A pump setup I'd create for using lakewater would cost a customer over a thousand dollars, but that's for something that will last a few decades, and runs without needing much attention from the homeowner. Three sprinklers probably wouldn't justify such an expense.