Water butt mains backup connection

Anybody here found a cost effective way to hook a water butt to the mains without falling foul of water regulations?

I want to setup automated irrigation with a water butt as the main water source but during dry periods when there is no rain I want to maintain a minimum water level via the mains to prevent the pump running dry and the ensure my plants still get watered.

I have a few ideas of my own yet to be put in practice, anybody out there already doing this who can share their appriach?

Thanks

 

One solution that comes to mind is what farmers use in their fields to fill water troughs basically a valve linked to a plastic float which releases the valve as the water level decreases

Sent on the go from my telephone

 

Thanks, this is the approach I am looking to take more or less, just not sure a) what sort of valve would be appropriate b) the consequences of having the mains on constantly and the resulting stress on the system.

As the valve cannot be submerged (water regs) the obvious solution is a float valve with an extended arm, but the arm would have to be very long and I think this would be cumbersome.

I came up with an alternative solution, with a half full plastic bottle of water attached to a valve by a chain which floats when desired water level is present, when the water level drops and the bottle is suspended in the air rather than floating the weight opens the valve and the minimum water level is restored. Once the bottle is supported by the water level again, the valve cuts off. The problem is I am having trouble finding a suitable valve, also valves can be quite expensive.

So again, if anybody had actually got a working solution would love to hear from them.

 

One of these the arm beween a and b can be bent, you connect water pipe onto the valve but you may need to but a through tap in the water pipe so you can switch it off when raining, the valve must be above the water line

 

I had considered the extended float arm. I was concerned about the fact that when the water butt is full the float would be submerged, which could cause stress on the valve and the arm. Also I remember struggling to find along enough arm, but I may not have looked hard enough.

 

Looks a bit like your average toilet cistern to me.

 

It is

 

Most of the one in my toilet are plastic, thoose in the pic are metal with a plastic ball float there're the one's which farmers use in water toughs

 

You aint seen my outside bog.

 

http://www.screwfix.com/p/pegler-prestex-float-valve-part-2/27627

Even this looks a bit modern

 

http://www.screwfix.com/p/pegler-prestex-float-valve-part-1/90110

Just found this

 

The problem I see is that (apart from it not being long enough at 21 cm) is that once the water butt is full (lots of rain) the arm will be extending down into the butt with the float submerged. I suspect this may cause stress on the arm and the valve.

Thanks for taking an interest btw = )

 

The below is what would really be needed for the extended arm approach, but then we are talking serious money:

http://www.tanks-direct.co.uk/equil...um_float_valve_2"_c_slash_w_drop_arm_&_float_

 

Why is the arm not long enough?

The arm just compresses a washer in the valve, so if the float is under the water the mains is shut off.
Cant see why this would put stress on the arm or the valve, especially if the valve is set at the top of the butt, where the water would overflow anyway once the butt is full.

 

Well lets say my butt is 100cm high with the valve at the top, a 21 cm arm would mean that the minimum water level would be at 79cm giving me 20cm'ish of rain water space (anything less and the mains kicks in)

That's true, maybe it won't cause stress. Something about the float being submerged for long periods of time made me uncomfortable.