Without going into too much detail the water pipe arrangment in my house is completely screwed up. Speaking to the neighbours it seems that all the houses in the development were done wrong from the start.

It looks like it's a case of starting from scratch.

Would this arrangement work?

I want to split the mains input off to the tank then pass through a check valve and then recombine after the pump. The idea is that there would still be water in the case of a power failure or fault in the pump, Under normal operation the pump pressure would close the check valve and water would be drawn soley from the tank but if there was no power to the pump the mains pressure would open the valve.

(Should I put a second check valve on the output of the pump?)

Yup, that will do it, you'll need to add some additional isolation valves but the basic principle is there.

You may want to add a stop in line with the non-return valve too, they sometimes start seeping and cause the pump to run continuously.

Thanks for that.

The isolation valves are just the ball valve type?

Thanks for that.

The isolation valves are just the ball valve type?

Yup in PVC or brass UP2U

You'll probably want to use maintenance unions on the pump too, so you can remove it easily when it goes wrong (it will).

Here in Bangkok, where loss of power is rare and almost never more than an hour or two, find manual shut off valves to be a positive solution and not an issue to turn them on for the infrequent occasions required. Water without pump is almost useless for more than filling containers in any case so waiting for water pressure to return is not normally a negative.

Yup, that will do it, you'll need to add some additional isolation valves but the basic principle is there.

pump setup 2.jpg

You may want to add a stop in line with the non-return valve too, they sometimes start seeping and cause the pump to run continuously.

Something else you may want to do if you use a lot of water outside for watering gardens, etc. Put in a Tee and add a pipe to the bypass line (the one with the check valve), so you can bypass the pump for watering. You would need to put it on the supply side of he check valve.

You want pressure in the house, but it doesn't matter much for watering, so why run the pump? You can save a lot of electricity and wear and tear on your pump.

Yup, that will do it, you'll need to add some additional isolation valves but the basic principle is there.

pump setup 2.jpg

You may want to add a stop in line with the non-return valve too, they sometimes start seeping and cause the pump to run continuously.

Something else you may want to do if you use a lot of water outside for watering gardens, etc. Put in a Tee and add a pipe to the bypass line (the one with the check valve), so you can bypass the pump for watering. You would need to put it on the supply side of he check valve.

You want pressure in the house, but it doesn't matter much for watering, so why run the pump? You can save a lot of electricity and wear and tear on your pump.

Yes, that's a good idea. The mrs will certainly use a lot of water on her flowers and veggies.

Yup, that will do it, you'll need to add some additional isolation valves but the basic principle is there.

pump setup 2.jpg

You may want to add a stop in line with the non-return valve too, they sometimes start seeping and cause the pump to run continuously.

Something else you may want to do if you use a lot of water outside for watering gardens, etc. Put in a Tee and add a pipe to the bypass line (the one with the check valve), so you can bypass the pump for watering. You would need to put it on the supply side of he check valve.

You want pressure in the house, but it doesn't matter much for watering, so why run the pump? You can save a lot of electricity and wear and tear on your pump.

Provided you have useful pressure from the main supply - unless of course a low pressure flow is suitable for your watering jobs.

A simple bypass in piping terms no ?

Yup, that will do it, you'll need to add some additional isolation valves but the basic principle is there.

pump setup 2.jpg

You may want to add a stop in line with the non-return valve too, they sometimes start seeping and cause the pump to run continuously.

Something else you may want to do if you use a lot of water outside for watering gardens, etc. Put in a Tee and add a pipe to the bypass line (the one with the check valve), so you can bypass the pump for watering. You would need to put it on the supply side of he check valve.

You want pressure in the house, but it doesn't matter much for watering, so why run the pump? You can save a lot of electricity and wear and tear on your pump.

Provided you have useful pressure from the main supply - unless of course a low pressure flow is suitable for your watering jobs.

I have my bypass with a leg to the pump-pressured side so that I have the option of natural flow from the public supply (generally low pressure for me -- 20 psi, but fine for watering) or open a valve and have full pressure (40 psi) for things like washing cars and pavement.

I try to think of every possible combination and permutation and put in pipes, valves nd check valves to accommodate it all. Of course your system might end up looking like the guts of a nuclear submarine . . .