Add 2nd House to Well

Old 04-03-21, 12:59 PM
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Add 2nd House to Well

My property has one house, with a second house under construction 300 feet away and approximately 50 feet higher in elevation. I need to use the same well for both houses. The existing house has a 50 gallon pressure tank located at the house. What would be easiest (cheapest) setup to get water to the new house? A single larger pressure tank for both houses at the well? I am in a bit of a sticky situation as some huge unexpected expenses have cropped up during construction (County forcing me to pave the driveway and state forcing me to replace existing septic system with an ATT system) and I'm about of of money for the project.
Old 04-03-21, 01:42 PM
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Welcome to the forums.

You need to make sure there is enough yield from the pump to support two houses.
Most typical well pumps will struggle trying to serve two houses.
Old 04-04-21, 06:44 AM
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First I would confirm in writing that tying the second house onto the well is permitted. Local zoning might approve it but many banks do not finance houses with shared wells.
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Old 04-04-21, 07:28 AM
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I live near a quarry and have dealt with a few homes having water / well issues (including my own), as well as being a Realtor-
Eh, that's going to be tough. In addition to the points above, here are the issues I see.

1) most well drillers will bore a well deep enough to have sufficient flow to serve 1 house; since well drilling is expensive, very few people will pay to have a well that produces 200% capacity for a house.

2) In situations where there is limited flow, the well will often be drilled deeper so that there is extra storage capacity in the well bore, BUT that requires dropping the well pump down to access the "reserve," and switching to a higher horsepower pump because the deeper the pump is, the harder it is to lift water up to the house.

3) That added 50' lift to the other house means you would probably can't use the existing well pump to push water to the new house- that additional 50' in height will likely require a new well pump.

4) The cost for running a 300' water line in a trench is not trivial.

So, what I think might be workable (but perhaps not permittable as a permanent solution) is what I've seen done when local homes lost water- a temporary 250 to 500 gallon "water buffalo" tank fed by a neighbor's garden hose. connected to the home water system using a shallow well (i.e. cheap) jet pump.
Basically, the neighbor's well fills the 250 gallon tank during the night at a trickle of around gallon per minute, then a float valve shuts off the flow.
In your situation, I'd guess you'd place the buffalo tank 100 feet from the existing house, and then have the jet pump 200 feet from the existing house so you've got 100' for the power, and 100' for the jet lines, and 100' for the water supply line. (Actual distance would depend on whether the temporary wiring or temporary plumbing is cheaper)

That being said, that kludge fix will cost a good fraction of the cost to drill a well (VERY much depends on your area...)

The height difference of 50' means you can't use a shallow well jet/suction pump (limited to ~32 feet due to vacuum/atmospheric pressure).
With a run of 300 feet, you're going to have a lot of resistance/flow loss from such a long run.
I think the only solution will be short term, (i.e. you're going to have to dig a well eventually) but
Old 04-04-21, 10:01 AM
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If you go the route of the water buffalo tank (cistern) it is possible for the existing pump to continue to serve your house with a minimum of modifications.

Put the water buffalo tank near the new house (probably no more than 50 feet) and at the elevation of the new house. The new house will have one new pump with shallow well capability to draw from the unpressurized buffalo tank and go into the house system with the usual 60/40 PSI pressure tank.

The existing pump maintains the 60/40 PSI for your house using a variety of simple methods:
1. The resistance of the long run to the buffalo tank,
2. Having to pump uphill 50 feet to the elevation of the new house,
3. A flow restrictor such as a valve that is partially closed,
4. A time of day valve to limit filling the buffalo tank for late night hours,
5. A float shutoff valve when the buffalo tank gets full.

(You might not need both 3 and 4.)

Hopefully the existing pump can put something into the buffalo tank if nothing is being draw in your house.

The buffalo tank can remain in place if the new well eventually drilled for the new house does not have adequate yield.

Last edited by AllanJ; 04-04-21 at 10:19 AM.
Old 04-05-21, 07:52 AM
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Shared well may not even be permissible, but if it is, then think what happens if and when you sell either or both houses. New buyers may (rightfully) be concerned about sharing a well. More lawyers will be needed, at the very least, and that's never a good thing!

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