Recently we had a client with a concrete tile roof which had material that had been leaching into the water tank. In doing this job we found something we weren't expecting.
The house was 20 years old and had a concrete tile roof, the gutters ran down to 100mm PVC and ran under ground and then came up the side of the water tank and into the tank which is pretty much normal practice.
We were installing a first flush system and dug down around the main pipe to the tank, it was buried 1 metre below the ground. As we cut into the pipe we found it mostly blocked up with sludge from the concrete tile roof which was a green colour. The majority of the material was concrete coloured grains, leaves, sludge and a dead bird!
What surprised us was the volume of material in the pipe. This was obviously enough to not be washed up into the tank and contaminate the tank. But all the rain water entering the tank however had to pass through this lovely filter of sludge – see the photo.
Fortunately we installed a first flush system; this in future drains the water from this “always full” pipe and diverts it to a simple drain. This converts a “wet” system into a “dry” system and also means the first flush off the roof goes to a drain and not into the water tank full of clean water.
It rained overnight and the next morning we pulled the end of the first flush pipe off and about 40 litres of black sludge surged out the end having flushed all the pipes from the roof. This sludge was contaminating their water. So if you have a concrete tile roof and want to stop the concrete fines building up in your pipes, give us a call on 0800 787 392.
We can come out and do a free site visit and find solutions that will help you drink the healthiest water possible.