So to answer some of your questions first…
- Rate of return on a well will vary widely. It will depend on your well, point, pump, etc. With a well, you will typically have a holding tank. This is where your pressure is going to be driven from. Typically, it holds a certain amount of water and the pump itself will kick on when the pressure drops below a set point. It will kick off when the pressure is built up to the cutoff point. So your pressure will drop and raise. If you have one sprinkler hooked up, you would probably notice the range extend and slowly decrease until that pump kicks back on to build up that pressure again. I think there is a way you can see what it is pumping (GPM) by letting the tank fill to full pressure. Then fill up a bucket until the pump kicks on. You would then determine the time the pump runs before it shuts off. With those numbers, you could technically figure out the GPM. But besides that, pressure may be an issue.
- If you are able to, I WOULD get a second well to run your irrigation. You could technically get a bigger well with a larger pump to increase both GPM AND just as importantly, pressure. If you have an ‘on demand’ pump for this second well, you wouldn’t need any holding tank and could maintain a more constant pressure. See notes below about my dad’s irrigation pump/well. The second piece to this is, you’ll keep the load off your house well/pump. Depending on what your house well/pump can handle, you may be running it hours a day to irrigate. I would rather my ‘irrigation’ pump/well have issues then my house… that was my conclusion after some sole searching on how I wanted to do mine.
The nitty gritty (history)….
So let me explain my thought process when I went through this sole searching…
My dad and I both have wells. He is in an area where the water table is very shallow (sandy soil). I’m in an area where the water table is much deeper. He is able to get away with an external pump (shallow well) but I need my pump down by the well point.
When I was debating on adding irrigation to my yard, I did some tests to see what my GPM from the pump was. I’m at about 5.5-6.0 GPM. Depending on the sprinkler heads I would use, I could run maybe 2 heads. I have 2.5 acres I was planning for so if you do that math, I would need more zones that I would like to admit.
I started to think some and even if I did 2 or 3 heads per zone, I would beat my well pump up. That thing would be running … something like 8 hours a day if I did each zone every 3 days (or something like that). I did a lot of math and mapping out. My old house was a well as well but it was external (shallow). So replacing it was like a 15-minute job. For the deeper ones, I’m not sure if I would do it or not. The pumps are more money and not sure of the time it takes to replace. So I decided whichever way I went, I didn’t want to beat my pump up and potentially have it go out prematurely.
I decided to investigate a second pump, JUST for irrigation. If I beat this pump up (or run well dry), so be it. I rather IT go out then my house well. My family (wife and kids) needs the water more than my grass. So I knew whatever way I was going to go, it didn’t include running my house well to irrigate that much property. For a small yard, maybe.
Pricing out a company to come and drill me a second well and add the pump, it was over 10K. I wasn’t about to spend that. Though having a backup to my house well seemed like a good idea. But I still couldn’t justify the cost.
So then if we check on my dad, he has close to an acre. Out there (about 20 miles south of me), he only needs to go 20-30’ feet down maybe? You can find someone and pay them $300 to come out and drill you a shallow well using a high flow pump. The guy installed a slightly larger point and piping for him. My dad bought a larger water pump and he can push out something like 20 GPM at 60PSI. It is separate from his house and requires no holding tank. He zoned out his yard to work with the full output of his pump. So he was able to have a secondary pump for very little compared to me. It runs on demand and kicks on by his irrigation controller. That simple.
I would say, if you can get an inexpensive well to run your irrigation, I would. It doesn’t need to be deep enough to have ‘drinking quality’ either. You’re just irrigating (IMHO). But it really depends your water table.
If we go back to me, I ended up putting in a 11K gallon pond. I wanted to put one in eventually and this was my time. All my rain water from gutters go into a few different 4” drainage pipe and feed into the pond. Usually with just a small amount of rain, that pond overflows. I have overflow drainage at the lowest spot in the pond and even a true spillway just in case.
In the pond, I have a feed to my irrigation pump which feeds the main line to the various zone controllers around the property. I have about 1/3 of my yard irrigated and about 1/3 with piping ready to install the other sprinkler heads. Started last year and hopefully will finish his year.
For me, it works since I only water enough to keep the grass from going dormant or to water in fertilizer/chemicals. I’m not out there watering daily by any means so that 11K pond holds enough water for me and always keep plenty for the koi and minnows I have in there now. Plus, my kids get to play in the shallow side of the pond as well as feed the fish!
But yes, I would try getting a separate irrigation well just for your yard. I think it is the cleanest and best way to keep that load off your house well.
** DISCLAIMER – I did not proof read any of this… haha
I'm happy to answer any questions that I am able to though. I spent months going through possible ideas and my first / best option was to get a secondary well. I just couldn't justify the cost. I know I know... but then here I am putting in a big pond... I already had the tractor though and had plans to do it anyway. So it all just kind of worked out for me.
