Well water for our new Eco House instead of mains water - how to connect it?

[Pedro 2]

I am not having mains water for my new build. We are drilling a well to provide our water. Installation of Grundfos 4" submersible pump (~25L/min - 16 bar). I understand that you need to install a 50 ltr or 100 ltr pressure tank to control the flow from the well pump and even out the flow rate. We will have the well drilled between the house and the garage/workshop and we plan to have the water connection from the well to the garage/workshop - then bring all facilities (water, electric, sewer, Broadband) along a trench from the garage/workshop to the house. (Map attached showing the distances, blue line showing the path of the water from the well). 

 

Questions:-

With the well just connected to the workshop/garage could we place the pressure tank in the workshop/garage, and would it provide enough pressure and flow to the house? This is the preferred option.

What size of pressure tank would we need (there will just be the two of us living in the house most of the time)?

 

If the above does not work could we just place the pressure tank in the house with a separate connection direct to the house (dotted blue line) and leave the water connection to the garage/workshop to work directly from the well pump.?

 

Your thoughts and views appreciated. 

 

 

house and garage map.pdf

[JohnMo]

Ours is about 25m to pressure tank (50L), then after the filters it splits, one side to house, about 8m, the other side goes to garage about 70 to 80m.

 

Loads of flow, no issues at all.

 

Once drilled and you run the water out for a week or two, you will get the water tested, and appropriate treatment and filters.1

[Nickfromwales]

26 minutes ago, Pedro 2 said:

With the well just connected to the workshop/garage could we place the pressure tank in the workshop/garage, and would it provide enough pressure and flow to the house? This is the preferred option.

What size of pressure tank would we need (there will just be the two of us living in the house most of the time)?

I'd prefer the tank in the garage so the water isn't always sitting at 'room temp' in the heated envelope of the house. Far better if you are using this for human consumption as you can then get a glass of cold-ish water at least vs cold / tepid. To be honest I'd have it in a shed with a bit of insulation to make sure it was cold, just not allowed to freeze, but how much you worry about this will be dependant on how you drink water in the house. If you have a cold water drink / ice dispenser in your fridge and use that for quenching thirst (or bottled water) then the issue very much goes away.

[Nickfromwales]

Oh, and I'd go for no less than 100L expansion buffer (cold mains accumulator) tank as around 50% of that will be air not water.

 

[Nickfromwales]

22 minutes ago, JohnMo said:

Loads of flow, no issues at all.

What pressure does the pump cut off at? 50L vessel will be roughly 50% air so interesting to hear you manage well. Has it ever bottomed out with use at the home and say an outside tap > garden hose in use ever?

[JohnMo]

7 minutes ago, Nickfromwales said:

What pressure does the pump cut off at? 50L vessel will be roughly 50% air so interesting to hear you manage well. Has it ever bottomed out with use at the home and say an outside tap > garden hose in use ever?

We control around 2.5bar. Standing next to vessel, when someone opens at tap pressure starts to fall, about 20 secs later you see the pressure gauge rising. It continues a few seconds after the tap closes. 

 

Feels just like a mains connection, in use. We do have two huge banks all planted and the first summer we watered the lot most nights. 2 hose pipes running for an hour or so, at a time. I did get a little nervous about running well dry, but no issue.  But well pump is down at 40m ish and have a Loch across the road about 6m down from the house. So in reality we should never run out - I hope.

 

Wells have an issue - no electricity no water. Or you need big storage and the issues that comes with. So have generator, house battery and plenty of solar.

[Nickfromwales]

So location and recovery rate are the big Achilles heel here then. Thanks for the explanation.

[Pedro 2]

1 hour ago, JohnMo said:

Ours is about 25m to pressure tank (50L), then after the filters it splits, one side to house, about 8m, the other side goes to garage about 70 to 80m.

 

Loads of flow, no issues at all.

 

Once drilled and you run the water out for a week or two, you will get the water tested, and appropriate treatment and filters.1

Thanks for the information and your experience with water from a well. It looks like my preferred option will work; pressure tank in garage and piped to the house will work. 

[FarmerN]

Check local records, local knoledge that your water quality will be OK.

I spent a lot drilling a borehole, good water supply at 50 M but it was so sulphurous it was not fit to use and treatment costs prohibitive.

If you left the water in a bottle over night it stank of rotten eggs next morning. I should have guessed the water was 'special' as there used to historic health spa next door!

[Pedro 2]

I have had a BGS survey of the geology which looks good, drilling to the Tunbrigewells sandstone formation 50m down which provides good water to surrounding wells in the area.

[Pedro 2]

Just been discussing our plan with the driller, and he points out the the garage area is 3m below the house level. If we have the pressure tank in the garage and take the water pipe from there to the house - we will have less pressure in the house. It looks like we will have to go from the well to the house (both on the same level) and then take the pipe along the trench with all the other facilities to the garage to have the best pressure of water in the house.

 

I hadn't considered the elevations!

[Nickfromwales]

4 minutes ago, Pedro 2 said:

Just been discussing our plan with the driller, and he points out the the garage area is 3m below the house level. If we have the pressure tank in the garage and take the water pipe from there to the house - we will have less pressure in the house. It looks like we will have to go from the well to the house (both on the same level) and then take the pipe along the trench with all the other facilities to the garage to have the best pressure of water in the house.

 

I hadn't considered the elevations!

You can mitigate by installing bigger accumulation vessels and fitting a much bigger pipe to the house. 3m isn’t ‘huge’ tbh. It’s just down to how much space you have to lose in the house vs beefing things up at the garage.

 

Can defo be done. 

[JohnMo]

56 minutes ago, Pedro 2 said:

3m below the house level

0.3 bar different from being at the same level. If your pump is 50m down the borehole, you are doing not much extra work lifting an extra 3m. Just set the the pump starts and stop threshold for pump start and stop a little higher - if you need.

 

Don't fret.

[Conor]

Out of curiosity, what the reason you're not using mains water?

[JohnMo]

On 19/03/2025 at 20:57, Nickfromwales said:

To be honest I'd have it in a shed with a bit of insulation to make sure it was cold, just not allowed to freeze, but how much you worry about this will be dependant on how you drink water in the house

Exactly what we did. The pipes in the house (to each wet room) all go under the floor insulation (cast into the concrete slab) as well, so tap water is about 6 degs after a couple of seconds all year round.

 

On 19/03/2025 at 20:59, Nickfromwales said:

no less than 100L expansion buffer

Just looked at ours it is 100L not 50L as stated above.

[sharpener]

On 19/03/2025 at 20:23, Pedro 2 said:

If the above does not work could we just place the pressure tank in the house with a separate connection direct to the house (dotted blue line) and leave the water connection to the garage/workshop to work directly from the well pump.?

 

There is an alternative to a pressure tank I think, one of these pressure controllers. 

 

Normally the pipework is pressurised. When a tap is turned on and the pressure drops its starts the pump, then a flow switch keeps it on until the flow reduces to less than 0.5 l/min, a short overrun then re-pressurises the pipework and the built-in NRV keeps it so.

 

We bought one of these Clarke controllers (the cheaper one without pressure display) as a direct replacement for the one originally supplied with the Stuart Turner jet pump which is installed in the garage. The user experience is just like having mains water. I see no reason why it would not work with a downhole pump. If anything it might be better bc there is a longer pipe run to store the water at pressure.

 

As others have said depending on the water analysis you will need filters and maybe a UV steriliser.

Edited March 22 by sharpener

[JohnMo]

On 19/03/2025 at 20:23, Pedro 2 said:

If the above does not work could we just place the pressure tank in the house with a separate connection direct to the house (dotted blue line) and leave the water connection to the garage/workshop to work directly from the well pump

Just reread this, maybe not. The pressure vessel is there to stop a short open of a tap firing up the pump to reduce start cycles, but so give immediate flow when you open the tap. The pressure vessel goes between down hole pump and filter system. Filters goes before any users.

Edited March 22 by JohnMo

[Pedro 2]

11 hours ago, Conor said:

Out of curiosity, what the reason you're not using mains water?

It was very expensive to connect up even though we were only 100m from the mains. Also my wife won't drink it, too chlorinated! So the well option was only 30% more than mains connection!