Low Yield Well

[ebarrieau]

Hi Everyone,

When I moved into my house three years ago I had to immediately replace the well pump because it was constantly hitting its internal overload switch - it was ~20 years old at the time, our well driller told us that it was likely just that the pump was old and that it wasn't a symptom of a larger problem. We have never had an issue with our well after replacing the pump and have never run out of water. I am having landscaping work done and will need to water the grass for a few weeks and I was worried about doing that on a well, so I bought one of the Eno Scientific sonic level sensors to track the well depth and get an idea for recovery rate and was shocked to see that we produce less than 0.5 GPM. Needless to say I won't be watering the lawn any time soon, but now I am worried about the long-term stability of my well. The well driller who replaced my pump when I moved in told me that the wells in this neighborhood are notoriously low yield, so I don't think drilling a new well will fix the issue.

I have talked myself into installing an intermediate storage tank in my garage with a boost pump so that I am not drawing down the well as much and to hopefully maintain my current yield. I am an engineer and plan to build the control system for the pumps myself and use the Eno Scientific level sensor in the control loop so I don't draw the water down too far. My question is about how much I should be pumping at a time to get the most yield out of my well - as you can see in the graph output from the level sensor, the production when it is ~50ft below static head is around 0.5 GPM, but as it approaches its static level the production slows down significantly. How much should I plan to pump into the storage tank to maximize my yield without stressing the well by over-pumping it?

My second question is about the placement of the new tank relative to my current water filtration. I am probably going to move my sediment filter before the tank and my charcoal filter after the tank, but should my water softener be before or after the storage tank? Also because I am going to put in a rather large tank I am considering adding a dosed chlorination system, does that change the placement of the water softener?

Thanks in advance for any help or insights you all have!
-Ethan

Well Details:
Drilled: 400ft
Pump Place: 300ft
Bedrock: 20ft Granite
Pump: 5GPM 3/4 HP
Static Water: ~60-65ft from top of well casing
Production: ~0.5 GPM
Well was hydro-fracked at the time of drilling in 2000-2001

 

[Valveman]

You get the most from a low producing well by keeping it pumped down. When the water level is pulled all the way down the down hole pressure is lower and more water can flow into the well. Pretty cool gadget to check the water level, but really isn't necessary. Just use a Cycle Sensor to shut the pump off when the well is dry, and it has a timer that restarts the pump as per setting. I recommend a setting of about 20 minutes as complete water level recovery isn't the issue, the amount of water the well can produce is.

You want all filters and softeners after the pressure tank/pressure switch. I would only inject chlorine if I had a water quality issue that needed chlorine. Otherwise it just adds a bad taste and toxicity to your water.

You will have a large storage tank, so a large pressure tank is not needed. You will actually get stronger constant pressure from a system with a small tank like the PK1A kit. This kit can supply constant pressure from a jet booster pump or a submersible. Many people install a sub in the storage tank as the are more quite, and deliver more pressure per the horsepower.

 

[ebarrieau]

Hi Valveman,

Thanks for the detailed reply and that confirms my thoughts that the well will produce more when it is pumped down. I have been doing a lot of reading on this and the two commercial systems I have seen (Well Manager and Epp Well Solutions) make claims on their website that keeping the well in a pump down state can have long-term water quality and well yield effects - is this something I really need to worry about?

 

[ebarrieau]

Also, I saw your response to someone on a different forum to a similar question and your argument to use a standard submersible pump and CSV instead of a "fancy" variable speed pump is very convincing and is the route that I have decided to go.

 

[Mitchell-DIY-Guy]

I don't know what kind of property you have, but my old business partner had a similar issue at his home in East Arlington, VT. What he did was bury a 1,000 gallon tank outside. My guess is it was concrete, but I think today you'd use poly.

 

[Valveman]

Hi Valveman,

Thanks for the detailed reply and that confirms my thoughts that the well will produce more when it is pumped down. I have been doing a lot of reading on this and the two commercial systems I have seen (Well Manager and Epp Well Solutions) make claims on their website that keeping the well in a pump down state can have long-term water quality and well yield effects - is this something I really need to worry about?

In some wells the sediment will get stirred up if the water level is pulled down below a certain point. Your water level detector could probably work with a well like that. But most times we can tell by the amps on the Cycle Sensor what the level is and set it to turn off the pump when the amps are at that level, which is not as low as when the well is dry.

But most wells can be pumped dry or have the pump set at the level you want without causing any problem. And it is the best way to get the most water from a low producing well.