back flushing a water line.
I am talking about backflushing the water line between the water main under the street, and the water meter in the basement of the house. I have never done backflushing in this situation but I think it could be helpful. I have very low flow rate and pressure in my house. To my knowledge my water line, 100 ft in length, is nominal 1/2 inch copper water tube type K, installed when the house was built in 1960. Everyone tells me that I need a larger water line, say 3/4 inch. However I have looked up the pressure drop for 1/2 inch water line. For 3 gallons per minute the pressure drop over 100 feet of water line should be about 7 psi. In an actual test of my water line, done by a City water technician, the flow rate was just under 3 gallons per minute under the full pressure difference of 60 psi. My existing water line seems to offer 8.5 times more resistance to flow than a clean water line would. Before I go into the astromical rip-off cost of having the water line replaced, I want to investigate backflushing. Maybe backflushing would clear out deposits in the water line and restore it to normal operation. I do not think air would be used in this process. The steps would be to shut off the water valve just before the water meter. Remove the water meter and use appropriate fittings (all planned out before hand) to connect a pressurized water tank to the fitting where the water meter was removed. In the meantime you need a method to prevent water from pipes in the house from running down into the basement. Then open the water valve. Then apply maybe 80 psi water to cause backflow into the water main. Only a professional plumber, preferably a plumber from the City water department, should carry out this process. The amateur should not try this! The City water department should be consulted before this process is done. But I think there is a chance that this simple process could solve the problem. The other thing to discuss with the City is whether the water stop valve out at the curb, or on your property line, is defective in the sense that it does not open fully and is restricting water flow.
Last edited by edward0608; 10-18-2012 at 05:16 PM.