One well, two cisterns for two houses

[eastglacier]

Hello all,
We currently have two cabins separated by about 400'. Each cabin has a 2500 gallon cistern that it is plumbed to. We have been getting by for 5 years hauling water and filling cisterns after we drilled a dry well. This past fall we dug a new low-producing well (1.5 gpm) that is about midway between the two cisterns. Each cistern has a float switch, but I can't seem to figure out the best way to fill them both with one well. Can somebody help me figure out our best option here? If it's helpful, one cistern is 40' vertical above the other.

Thanks for your time,
Nate

 

[Blue Oaks]

Would a trough valve in each cistern work?

https://www.amazon.com/Jobe-Valves-Megaflow-Valve-Yellow/dp/B06XHQCHTF/ref=sr_1_20_sspa?keywords=water+trough+float+valve&qid=1681158791&sr=8-20-spons&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc&psc=1&smid=A2HCHIE6U0W1ZN&spLa=ZW5jcnlwdGVkUXVhbGlmaWVyPUEyNU4yWTdVTzdFNk9LJmVuY3J5cHRlZElkPUEwODM4OTkwMVpQQzlKTUxOQ0lURyZlbmNyeXB0ZWRBZElkPUEwMzgzNjYxMklIWlBLTlNZQkNSQiZ3aWRnZXROYW1lPXNwX210ZiZhY3Rpb249Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[Sponsor]

 

[Valveman]

Yes a "trough valve" will work. Any type of float valve will work, but non-modulating is best. I use a float switch to operate a 24V electric "sprinkler" valve at each cistern.

Now to make a float valve or electric valve work, the pump will need to be controlled by a pressure tank and pressure switch and filling multiple tanks as different flow rates is greatly enhanced by controlling the well pump with a Cycle Stop Valve or CSV. A CSV would eliminate pump cycling when only one cistern is being filled at a time.

The well pump can either be restricted to 1.5 GPM or just use a Cycle Sensor and let the well pump run on and off according to the level in the well until both cisterns are full.

 

[eastglacier]

Thanks for the replies. Everything here makes sense, but I have a couple of extra questions. We plan to pump from the well to a pressure tank under the lower elevation cabin. From there, water line will feed each cistern separately. The upper cistern from there is about a 400' horizontal and 40' vertical (up) run for the water line from the pressure tank. With 1" line, will we have enough pressure, or will we need a jet pump? The pressure tank also has to be skinny to fit into the crawlspace- less than about 18" wide. Do we need to think of anything size-wise there other than small enough to fit?

Thanks again

 

[Valveman]

40' vertical only takes 17 PSI. Your normal 40/60 switch will be enough to supply the cistern without an additional pump.

Yes, size for placement should not even be a concern for a pressure tank. The tank needs to be as large as possible to reduce the cycling unless you control the pump with a Cycle Stop Valve. With a CSV the tank is almost a moot point however. So, with a CSV a little 4.5 or 10 gallon tank is all you need, and I believe both of those are 18".

 

[eastglacier]

Alright, a dramatic follow-up. A "plumber" came and hooked up a system similar to what was envisioned- a pump in the well, a pressure tank to tell the pump to run that then feeds both cisterns, and float valves in each cistern. Well, we seem to have a problem now. As was mentioned earlier, the well is low-producing (actually closer to 0.5 gpm when the pump was installed, ~700/gallons/day) and 150 feet deep, with static water level around 50'. For the past 5 years, use by the two cabins was about 700 gallons/week, so 350 gallons/cabin/week. Mathwise, we should have more than enough water, but it doesn't appear that we do. In the last week, we are again showing the cisterns down about 350 gallons each, which would indicate little to no water coming in. We believe the well pump is running constantly. When we turn off the breaker for a few hours, we get a handful of minutes of water spraying into the cistern, but then it seems like it may not happen again until we let the well recharge again. The pump that was installed was an extremely cheap pump that we had lying around (https://www.amazon.com/Hallmark-Ind...fos.18ed3cb5-28d5-4975-8bc7-93deae8f9840&th=1) as a stop-gap in case a pump we use elsewhere to pump water out of a cistern fed by a spring failed. The plumber claimed pumps were on backorder and he couldn't find one in less than a month and assured us that using our backup would be fine.

In the meantime, the plumber has disappeared and will not respond to calls, so we had a different plumber come by to look for leaks because we were losing water from the cisterns. Well, after digging up the cisterns and redoing the inlet plumbing, we are still losing water, and it appears that we are not recharging the cisterns at all, losing just as much water now as we were without having had a well. Apart from leaks, the only possibilities that we can think of are 1) the cheap well pump and 2) the well isn't producing any water. However, when we cut power to the well pump, it seems to recharge just fine. Any feedback would be greatly appreciated so we have something to work with when we call the new plumber on Tuesday.

Thanks in advance.

 

[eastglacier]

And another follow-up. Just got in touch with a well guy from the county over. He thinks that it's possibly a float valve problem. The current float has a ~16" (guessing based on memory) rigid metal arm attached to a brass nozzle. So vertical up position is about an almost 3' difference to vertical down position. He said that the pump will be activated when it's in the vertical down position and then won't turn off until it's in the vertical up position. These are 2500 gallon tanks, so 3 feet is approximately 1000 gallons in each tank. This would mean that if the tanks both hit that lower position at the same time, the well has to pump ~2000 gallons (+100 gallons/day use) to catch up, which would take 3-4 days of constant running by the pump at 700 gallons/day. Does that make sense?

 

[Valveman]

You can't count on the float valve or float switch to control the pump is a weak well. The well will always pump dry, and can be pumped dry many times before the cistern is full and the float switch/float get to the top and closed position. When the pump is running continuously and pumps the well dry, it loses prime and won't pick up water again until turned off and back on. You also cannot run a pump continuously when only getting 700 gallons a day, as that is less than 1/2 GPM and not enough to keep the pump/motor cool. What you need is a Cycle Sensor to turn the pump off when the well is dry, back on after a preset amount of time, and continue to do this until the cistern is full and the float switch/valve closed.

 

[eastglacier]

Ok, so it sounds like our pump might lose prime each and every time it turns on- right? If it pumps to dry because the cistern is calling for 1000 gallons and it can only give a handful? Then it'll run without moving water until turned off, even if there is water in the well? So, to test, we would just flip the breaker off and back on and we should get a

 

[eastglacier]

Should get a spray of water right away, as if the well has been recharging the whole time it's been fruitlessly on?

 

[Valveman]

Yeah. That 33 GPM pump is draining the well quickly. Probably also need to use a ball valve and choke it back to 5-10 GPM to get a longer run time before it pumps the well dry.

 

[eastglacier]

Ok, the original plumber told me that would burn the pump out faster to choke it down with a valve- I assume you disagree with that. Anyway, with a CSV, it seems like the float valve is kind of redundant unless the cistern is full- correct? In my system, if I were to set the CSV to limit pumping to 3 minutes at 5 gpm (with a ball valve) every two hours for example, that would keep my well, pump, and cisterns happy, correct? 180 gallons/day is almost twice as much as is used daily, and 1/3 of what is produced by the well. Thanks again!

 

[Valveman]

Choking a pump is a good thing! That size pump only has to be pumping 1 GPM to stay cool. It is much easier on the pump, as shown by the reduced amps to use a valve and restrict or "choke" the pump. Just do not close it to less than 1 GPM and the pump will be happy. How long the pump runs is also important. Longer runs are better as pumps like to run continuously. You only need to choke the pump back enough that it will run for a few minutes instead of a few seconds to pump the well dry. The CSV (Cycle Stop Valve) will work WITH the choke valve. The choke valve limits the max flow from the pump, the CSV limits the minimum flow tp keep the pump cool and allow the use of a very small pressure tank.

You also need a Cycle Sensor on the well pump. https://cyclestopvalves.com/pages/cycle-sensor-pump-monitor
It will also work with the choke valve and CSV. But it doesn't quite work like you said. You set it to low amps on the Cycle Sensor to shut the pump off when the well runs dry. Then you set the restart delay for like 20 minutes, to let the well recover some before the Cycle Sensor restarts the pump. How long the pump runs is determined by how much you have the pump "choked" back to produce, and how many gallons are in the well. Choked back to say 5 GPM, if there are 100 gallons in the well the pump will run for 20 minutes. 10 gallons in the well and it will run for 2 minutes. Either way, the Cycle Sensor will just keep shutting the pump off every time the well is dry, then turn it back on in 20 minutes until the cisterns are full. Once the cisterns are full, the float switches shut off the solenoid valves that fill the cistern, and the pump fills the little pressure tank to 60 PSI and shuts off.

A Cycle Stop Valve can be even more important on the booster pumps, as they produce more water and can cycle even more. A Cycle Sensor can also be used to protect the booster pumps in case the cisterns run dry.

 

[Reach4]

Ok, so it sounds like our pump might lose prime each and every time it turns on- right? If it pumps to dry because the cistern is calling for 1000 gallons and it can only give a handful? Then it'll run without moving water until turned off, even if there is water in the well? So, to test, we would just flip the breaker off and back on and we should get a

A submersible pump does not need priming, so you will want a different word. You are concerned that the pump will start sucking in air. You don't want to do that for long. That is why the cycle sensor was suggested-- to shut the pump down for a while if you run out of water.

 

[eastglacier]

Ok, that makes sense. Is powering the pump off and then on a good way to test if it was sucking in air? If it pumps water, then the well recharged fine but the pump was air-locked (or some similar term) so couldn't push water up? Or am I missing something?

 

[Bannerman]

The only way a submersible pump could suck air, is when the water level in the well has dropped down to the pump's intake screen so the pump is drawing in air instead of water. If shutting off the pump for some time results in the pump being able to pump some water for awhile, that indicates the well has recovered somewhat, but there was again too little water above the pump and so the pump was sucking air again once the water level dropped down to the pump intake.

The Cycle Sensor that was suggested, will automatically shut off the pump once it begins to suck air. It also has a recovery setting so you can program an amount of time to allow the well to recover before the Cycle Sensor reactivates the pump to allow additional water to be removed before the water level is again depleted to cause the CYcle Sensor to again shut off the pump.