2 residences on one well

[jphillips]

2 residences on one well. Is this a good option. I am planning on drilling a well on my property. The wells in my area are usually 30'-40' deep and pump at 20 gpm. I am building a 3 car garage with a 950 sq ft. unit as the 2nd story. Next summer I plan to build an 1800 sq ft cabin next to the garage. So the pressure tank will be located in my garage's furnace room. When building my cabin should I install another tank in the basment or just run a line to the cabin? Total, the garage unit will have a full bathroom and a kitchenette and the cabin will have 2 1/2 bathrooms with a full kitchen. This is a second home and will be used on weekends and about 10 weeks a year.

 

[Bob NH]

There is no problem with two residences on one well, especially since you will own and control both residences.

I would run a good size pipe (such as 1 1/4" poly) to the cabin. Because the cabin and the apartment over the garage will be essentially separate occupancies, and will not know or care whether the occupants of one are using the shower or flushing the toilets when someone is showering in the other, I would also put an 80 or 119 gallon bladder tank in the cabin.

Because of the seasonal use where total power is a small part of the cost, this might be a good application for a Cycle Ctop Valve (CSV) and smaller tank. The pump with a CSV should be sized for 100% demand but not oversize because you are going to run it for more hours than you would without the CSV. I would pick a submersible pump that provides a little more than maximum demand at 55 psi and will deliver 65 psi or so at the low end of the manufacturers recommended flow rate. Three standard showers at the same time, with flushing toilets and dishwasher should not exceed 12 to 15 GPM.

For your shallow well, you should not get a standard "big box - off the shelf" pump. It will deliver too much pressure. You need to match the pump to the well and demand. That is even more important if you use a CSV.