Water tank. Divert water to mains.

[totoblue]

It seems to me that we are trying to make a simple task complicated. I'm thinking 'forget automatic switchover'

You could get the plumber to put one of those flexible stainless hoses near the tank so you can disconnect the toilet from the pump and reconnect to a mains tap nearby. That would be cheap, satisfy water restrictions and no problem with contaminating the mains. Only downside is that it is manual.

You could also have a separate small tank that had mains backup, was fed from the pump, and was located high enough to have gravity flow to the toilet cistern. That way you could still pump your main tank's water onto the garden, and wouldn't need two pumps.

BTW my pump (used only on the garden) doesn't have a pressure switch. It is one of those QB60 pumps you can buy on Ebay - I paid about $60 delivered. It is plumbed with irrigation pipes and turned on and off with a wireless remote switch from Bunnings. I was a bit dubious about the range before buying it, but it works very well and it doesn't seem to be phased by walls, windows, roofs, ground etc between the remote and the switch. I was cleaning out a small length of roof gutter recently (with tank water - there was a bit of gunk in the gutter from some work I was doing) and I was up a ladder with the hose and the remote and it worked fine despite there being roof, guttering, wiring, window, steel patio railing, concrete patio etc between the transmitter and the receiver. The remote has batteries obviously (note Bunnings don't sell batteries to suit!) but the switch is powered by the mains that it switches. IIRC the remote and switch was $50-odd plus a couple of dollars for an extension cord to connect to the switch.

[Mcblurter]

I got a quote from a company who sell tanks but also connect tanks up to toilet etc. Am looking at a 2400lt waterwall tank. Will need to connect two downpipes to it, one right where tank will be, other from about 6mt away. I asked for a quote on manual and auto and wanted a detailed itemized account, which they didn't do. Quote has come in for the princely sum of $5800 (inc GST)
Tank is 1250, rainsaver with pump is about 1500. Has a list of other stuff, but for labour they are charging $2900 . Geez for this amount might as well put in solar hot water or something that will actually recoup my money, rather than just a feel good, save water, save the planet thing. Looks like everyone is cashing in on the $500 rebate. Will see what my elderly step father (he's nearly 80 and still plumbing!!) can come up with!!
Cheers
McBlurter

[wonderplumb]

A manual change over would be the easiest, when the water runs out, turn off one valve and turn the other on. On the mains side (this is in Syd. water area) you only need a DUAL check valve to protect the mains, which is different again to a DOUBLE check valve.

[pcal]

A manual change over would be the easiest, when the water runs out, turn off one valve and turn the other on.

I couldn't agree more. My system has a duo valve to provide both backflow prevention and mains isolation near the front door, and a ball valve that joins two taps together (one plumbed normally, the other directly to the pump). The two valves are placed about 10 paces apart - for maximum economy of installation - and I throw them manually when the tank level requires. I have previously described the system in greater detail in this thread [ http://www.woodworkforums.ubeaut.com...t=42806&page=3 ]

In practice, I only have to turn a couple of taps three of four times a year at most! Don't get me wrong, I love electrical and automatic (that is my trade after all), but why would you bother? Weigh up the maintenance, repairs, running, and additional capital costs against the effort of throwing a valve... No competition IMHO. If you buy the right pump (ie. one with built in 'run dry' protection) there is no downside even if you do forget to throw the valves. You just get reminded when the taps stop working

Pcal

[munruben]

I was over a friends house the other day and this is what he has done. He has connected a pump to his water tank outlet and connected a water pipe from the pump to one of his outside taps. When his tank is full, he turns the mains water off at the meter and turns his pump on to pump the tank water into his house via the open outside tap. He is not using a flow back valve and because his water meter is some 30 meters from his house he reckons he would not get a flow back contamination with the mains water. When his tank runs low, he simply shuts off his outside tap that is connected to the water tank via the pump and turns the main supply back on.
Seemed simple to me, does anyone see any problem with this method or suggest anything to improve it.
I have just had a 5400 Ltr tank installed and was actually thinking of doing it this way myself.

[wonderplumb]

He is not using a flow back valve and because his water meter is some 30 meters from his house he reckons he would not get a flow back contamination with the mains water.

Hi mate I dont want to sound like a 'know it all' or a 'do gooder' but it is essential that a backflow prevention device is installed to protect the authority's main from cross contamination. Your mates house could be a kilometre away from the meter but if you get a negative pressure in the line due to the authority doing routine maintainence or a main bursts you will find that the tank water will drain out back into the main, given the right circumstances. Any water pipe that is above the main (and 99% of them are) will drain back to the low spot. If the local water authority found this out your mate would be crucified!! I understand that in Brissy they are having a big drive to replace existing water meters with new ones that have a "DUAL" check valve integral with the meter to stop this kind of thing. The authority dont care if you poison your family or workers in a factory environment but will do anything to protect their water mains from contaminants. But then again tank water would HAVE to be better than the tap water in Brissy!!!!!!!!!!!!!!!!!!!!!!!!

[munruben]

Hi mate I dont want to sound like a 'know it all' or a 'do gooder'

Not a problem, I appreciate your input and advice. Now you have explained the way it works I understand the situation better.I will most certainly be putting a back flow valve in place when I do my own set up. Will pass on the information from this thread to my friend too so he can evaluate the need for a flow back valve.
Thanks again and thanks to all the others who contributed to this thread. Must admit I didn't have a clue before reading the posts in here.