Well and Pump Question

Hi all,

First, thank you all for reading this, hopefully you can help!


Here's the story. I live in northern California. In my yard I have a well...it's basically a big piece of 8' galvanized steel tube, buried in the ground. It's 8' wide on the inside, and is full of about 20 feet of water, and has a constant (but weak) supply. Essentially it's a storage tank, in the ground.

Right now there's an old pump, with TWO pieces of 3/4 or 1" PVC going down into some kind of contraption on the bottom. I pulled the pump and those lines out...they're toast, old, done, gone.

I want to be able to pump that water out of the well, and the I probably won't need to pump it any higher than say 10' above the surface of the water. In other words the surface of the water in the well is at about the same level as everything in my yard, so I just have to pump the water from the bottom of the well (20' deep), and then I'll branch it out all over the yard to different areas.

What I need help with is sizing the well pump so that it gives me sufficient pressure. And by sufficient pressure I mean standard hose pressure...maybe enough for two hose outlets.

Should I use a 220v pump?

What about the contraption at the bottom of the pipes...someone said it's a foot valve?

Thank you!

What you probably should do first is perform a pump test to determine what the well will yield for water. If the well is only 20' deep, i would rent a gas pump,place a 15' section of pipe down the well with a foot valve on it or deep enough to be 5' off the bottom,plumb it into the gas pump,and start it up. On the discharge of the gas pump you should have a valve with a 10 foot section of pipe coming off of it so if the water starts to pulsate(over pumping the well) you can regulate it back until you have a steady stream of water coming out. Once you have a steady stream of water you can measure the flow rate with a five gallon bucket. Time how long it takes to fill the bucket in one minute,take that time and divide it into 60,then multiply that number by 5,and thats your gallons per minute. Let that water run for 4 hours and if it stays at the same rate after four hours it would be safe to say that is the yield of the well.

After the pump test and you have determined how much water can be taken out,you can then size a pump system. There is a guy here named Bob(speedbump) that can supply you with some good quality equipment.

SAM

The well/tank is about 1000 cubic feet, or about 7500 gallons.

The well will have a greater recharge rate if you pump it down.

You can use either a submersible pump or a shallow well jet pump. The submersible will be more efficient and will give steadier flow with varying depth.

I would pick something like a Goulds 18GS07 (or an equivalent less expensive pump) which is a 3/4 HP submersible. It will deliver a bit more than 20 GPM out of the bottom of the well and can be throttled down to about 6 GPM which will increase the pressure to about 75 psi. You should be able to easily design your irrigation system to operate within that range without a tank or any control valve restriction.

DO NOT buy a submersible well pump from the Big Box store unless you can verify that it has the characteristic you need for a shallow well. The pumps stocked by most Big Box stores will be for a deep well and will have too much pressure and too little flow for what you need.

You would need a 1.5 HP shallow well jet to get nearly comparable performance (actually a little less), but performance would drop off severely as you get to the bottom of the well.

You shouldn't need any tank, flow control, or regulator valve. Design the system so you have enough sprinkler heads on to keep within the 6 to 20 GPM range and turn the pump on for each zone. Most controllers have a pump control or you can hook one up to operate the pump off the valve.

If it will be possible to turn on the pump with all of the valves closed, then you can get an inexpensive relief valve (fixed 75 psi, 1/2" or 3/4") and put it on a tee off the main pump discharge line. That will keep you from "dead heading" the pump.

I would put a float switch in the well to prevent running it dry and damaging the pump. You could use that switch, with a range of 2 to 4 feet, to operate the well at a low level when using water. That will maximize recharge rate and therefore maximize available water.

I think a simpler setup would be a submersible pump,CSV,small tank with a pressure switch. If you are worried about drawing too much water from the well,i guess thats why you do a pump test. Even then a simple low water cut off switch will add plenty of safety back up. With the set up im suggesting it will allow you to use water to wash a car or whatever else you want to do with it, without having to manualy turn the system on. If you want to keep it simple thats the way to go!! And off we go........

SAM