How to valve multiple wells into a single supply?

[CountryBoy19]

BLUF: multiple low production wells powered by separate electric services need to be combined into a single supply. Goal: I would like to be able to mix the water from both at varying ratios.


The details:
Well #1, 1/4 mile from the house, drilled in the 50's, pumped into a 2500 gallon cistern, then pumped to the house. Electric supply, pressure tank, and pressure switch are in an outbuilding near well. Well recovery rate is less than 1/10 gpm, 200 ft deep 5" well, only 5 feet of casing before it goes to rock.
Well #2, near house, drilled in '94, was never properly recorded. Was abandoned on the 1st day living in the house "because it didn't produce enough and was salty" (according to original owners) so they trenched the 1/4 mile waterline from the old well/cistern to the new house.

The old well and cistern isn't keeping up with the demand from our family. The original owners, despite building a 6 bedroom, 3 bath house only ever had 1 kid. We have more kids and the well has been barely adequate the 6 years we've been here and it's starting to not be adequate.

I am currently waiting for water test results from the abandoned well. Currently the water level is 90 feet from the surface and the well is 280 feet deep. If the results come back salty but otherwise safe to use I'm wondering about diluting the salty water with the water from the other well to increase our supply and reduce the salt content enough to make it usable. Is there a type of mixing valve that would allow me to adjust the ratio of water from well #1 & #2?


What if the water results aren't salty and I just need to combine the 2 supplies, how would I do that?

Plan C is to consider treatment options or run the well for an extended period of time hoping the salt pocket eventually clears up.

Plan D, use it for livestock if the salinity is low enough.

For drinking water we have RO. The concerns with salinity are the effects on plumbing fixtures and the septic system as well as laundry cleanliness concerns. Any thoughts on my situation?

I have also considered fracking well #1 to increase production but don't know anyone in my area that does it. I have a great working relationship with a local multigenerational well company (I fabricate tools and equipment for his business and he takes good care of me). He said he doesn't know of a single company in the whole state that can frac a residential well.

 

[Valveman]

First you need a Cycle Sensor on each well to protect it from running dry and to be able to get as much water from each well as possible. Then with both pumps using a pressure tank and pressure switch, just stagger the pressures so the one you want to come on first is the highest pressure. Like the booster pump at 40/60 and the other well at 30/50. If you want to mix the water it would be best to pump both to the cistern in the amounts you want, and let the booster pump send water to the house.

Fracking might be worth a try, but you will need to talk to someone in your area that does that. Also, the kind of well you have does not sound conducive to fracking.

 

[Sponsor]

 

[Reach4]

How about using one well (A) primarily for direct drinking and as the source for the RO system. Maybe run the RO drain water into the cistern for B. Also use A, or RO water to water house plants. Use B for toilets, baths, laundry.

This may be more complex than you would want to do.

 

[CountryBoy19]

How about using one well (A) primarily for direct drinking and as the source for the RO system. Maybe run the RO drain water into the cistern for B. Also use A, or RO water to water house plants. Use B for toilets, baths, laundry.

This may be more complex than you would want to do.

We already have 10k+ gallons of rainwater collection/storage for watering duties. We use efficient appliances, limit consumption (if it's brown flush it down, if it's yellow let it mellow), etc. Our consumption is as low as it can possibly be without plumbing the RO drain water back into the source water. Unfortunately there is no way to plumb it back to the cistern. The cistern is 1200 feet from the house, would have to trench a waterline to it.

We don't do any direct drinking of the well water due to our karst Limestone, I know when it rains hard well production and turbidity go up leading me to believe surface water is finding it's way into the well.

Replumbing the house to run the toilets and laundry off of a second water source (either well #2 or rainwater) has crossed my mind but that's a lot of work for 3 bathrooms and the laundry is on a slab which would require cutting out concrete to replumb. If I can install a couple main lines and some sort of mixing valve in the crawlspace where both sources enter to balance the draw from both wells that would be a lot less work. I know flow can be balance with fixed orifices but the flow will only be balanced within a specific range of volumetric flows. So to size it for high flows it wouldn't reliably balance at low flows. Mixing the flows also reduces any potential salinity in well #2. Salinity is still an unknown at this point, an initial sample didn't show any salinity but the well hasn't been used in 29 years, I suspect if there is salty water in there it (being heavier) will be at the bottom of the well and I couldn't figure out how to capture a sample from the bottom by dropping a bottle down on a string (how I took the initial sample).

ETA, the RO system is a permeate pump system that only produces 3 gallons of waste water for every gallon of clean water so the RO waste water is already at a minimum.

 

[Valveman]

As you said it is next to impossible to mix two different flows in the right proportions when the demand changes. This is especially true at such low flow rates as one well only make 1/10th of a GPM. Mixing in a tank is best. You maybe able to mix in a smaller cistern and pump from there.

 

[CountryBoy19]

As you said it is next to impossible to mix two different flows in the right proportions when the demand changes. This is especially true at such low flow rates as one well only make 1/10th of a GPM. Mixing in a tank is best. You maybe able to mix in a smaller cistern and pump from there.

The recovery rate of well #1 (1/10 gpm) is mostly irrelevant because that one pumps into the existing cistern. The cistern is just 1200 feet away from well #2 and the house with nothing but a single water line running that distance which poses a challenge.

And the mixing problem was only an example of why fixed orifices won't work. Variable flow mixing valves are actually quite common, just not common for this application. I figured there was some clever trick out there to make it work but it sounds like the experts don't have any tricks.

I'm actually a bit shocked you don't have a suggestion involving some of your valves/products to accomplish this mixing.

 

[Valveman]

Sorry unable to help with this. I am familiar with mixing valves, but don't have any experience with them. If the flow rate of one well is very small compared to the other, you maybe able to use a pulse pump like a Chemtec to inject the smaller amount into the larger flow similar to injecting chlorine.

 

[Reach4]

What controls the pump at the far well?

Basically, I would think that the float that controls the operation of the inferior-water well would be lowered in the cistern.
The float that controls the better-water well would be set higher. Each would need a run-dry preventer.

 

[CountryBoy19]

What controls the pump at the far well?

Basically, I would think that the float that controls the operation of the inferior-water well would be lowered in the cistern.
The float that controls the better-water well would be set higher. Each would need a run-dry preventer.

Well #2 would never be plumbed into the cistern due to the distance I would need to run the buried line. The two supplies would be tied together on the pressure side.

But to answer your question, there is a float in the cistern that controls the demand for well #1. The float switch is attached to a relay which powers the pump through a CSV pump protector. The cistern is rarely ever full, the float is almost always calling for water. The pressurized water from the cistern is controlled by a traditional bladder tank and pressure switch in an outbuilding. The outbuilding is on a separate electrical service and meter due to its distance from the house. There are no wires connecting the outbuilding, well #1, or the cistern to the house, the only connection is a single 1200 foot long water line.

Also, I'm not sure how much well #2 produces. It wasn't enough for a family of 3 to get by without the addition of a cistern so I'm not expecting a large amount of water from it. I'm just expecting that the 2 wells combined will better satisfy our needs. The waterline from well #2 is already trenched to within 10 feet of the house (crawlspace) so I can easily add the last 10 feet and tie the existing water supply from the cistern and the supply from well #2 together. I just can't figure out how to actually valve it so I can get the water flows somewhat balanced.

FWIW, I have a full machine shop at my fingertips so even if I got some guidance on how to valve it but the specific valving I need is unavailable I can potentially machine it myself from stainless, bronze, or a combination of the 2. But I can't figure out how to make it work. Because each supply would be one its own pump/switch/bladder tank and never be at the same pressure I would almost need 2 pressure regulators that somehow provided feedback or balancing to one another, then each flow passing through a variable orifice like a spring loaded valve of some type that opens up with higher demand.

 

[Valveman]

I still think you could use a metering pump. The same kind of pump that injects chlorine into a pressurized line can inject the small amount from the low producing well into the stream of the higher producing well.

 

[CountryBoy19]

I still think you could use a metering pump. The same kind of pump that injects chlorine into a pressurized line can inject the small amount from the low producing well into the stream of the higher producing well.

Because of what the original owner told me (well #2 didn't produce enough) I don't anticipate well #2 producing much more water than well #1. I guess I will see when I get a pump dropped down and test the recovery rate. Additionally, well #2 is possibly the higher producer but that's the one that is salty. If anything I would want to inject 25-50% of water from well #2 into water from well #1. Will those pumps go that high?

While I have you here, I see check valves are recommended every 200 ft of depth, is that a hard limit or a suggestion? I will be using SIDR 7 1" polyethylene. I plan to put the pump at 265 feet (about 12 ft off the bottom) and I hate to cut the line and introduce a weak spot. I would rather put one at the pump and at the top (probably in the line outside the casing right next to the pitless adapter).

 

[Valveman]

Because of what the original owner told me (well #2 didn't produce enough) I don't anticipate well #2 producing much more water than well #1. I guess I will see when I get a pump dropped down and test the recovery rate. Additionally, well #2 is possibly the higher producer but that's the one that is salty. If anything I would want to inject 25-50% of water from well #2 into water from well #1. Will those pumps go that high?

While I have you here, I see check valves are recommended every 200 ft of depth, is that a hard limit or a suggestion? I will be using SIDR 7 1" polyethylene. I plan to put the pump at 265 feet (about 12 ft off the bottom) and I hate to cut the line and introduce a weak spot. I would rather put one at the pump and at the top (probably in the line outside the casing right next to the pitless adapter).

I think you can get fairly large injector pumps. They are metered so you can set the amount you want to inject into the other system.

People who make check valves came up with that idea of having one every 200'. Lol! Multiple check valves in a system is a recipe for failures. The only check valve you want in a water pump system is the one right on the submersible pump.

 

[CountryBoy19]

I think you can get fairly large injector pumps. They are metered so you can set the amount you want to inject into the other system.

People who make check valves came up with that idea of having one every 200'. Lol! Multiple check valves in a system is a recipe for failures. The only check valve you want in a water pump system is the one right on the submersible pump.

I thought it seemed excessive but this will also be the first time I've dealt with a pump set deeper than 200 ft. Thanks for the assistance!

At this point I think I'm done until I can get more info in regards to water quality and recovery rate of well #2. That will be a after I drop a pump down the hole. I had to order in 1" poly in a 300 ft roll, everyone was OOS so as soon as that comes in I will know more.

 

[Fitter30]

At the house with a water meter piped into each line before a new mixing cistern with solenoid valves. Each meter has a set of contacts that are measuring flow. With a level control in tank and would open solenoid valves. A program would read the meters and would mix the water supplies at a prescribed mix that is changeable in the program. As for as using one mixing valve it would be almost impossible because the water pressures from the two wells wouldn't be at the same pressure. Might work with a injection pump for potable water on the low flow well with the float system in house cistern with solenoid and injection pump. Don't think you want to mix the water before the tank as to not contaminate the other well if one fails and water would flow back to the wells cisterns.

 

[CountryBoy19]

I got the water test results back. Everything is normal or very low except sodium which is very high (107 ppm).

To quantify that I did a taste test and the salt taste was barely noticeable. I wouldn't drink the water, but I don't think the level is high enough to cause issues with fixtures, harm my RO water filtration system, or cause salt buildup or laundry problems.

But what is your take on it?

At this point I'm thinking I should be able to disinfect the well, tie it into my line, and not worry about mixing the water at a specific ratio. I can just set the on/off pressure switch for that pump about 3 psi higher than the other pump and that would make that the primary water source until the well runs dry and the pump protector shuts it off, at which point the pressure will drop another 3 psi and the other pump will kick on, pumping water up from the cistern.


Are there any thoughts on that plan?

 

[Valveman]

Sorry about the salt. But that pressure switch scenario will work well with a two pump system.