I was looking at installing one of those water powered pumps for a backup. The manufacturer says to have at least 40 psi. I had the water company come and check my pressure and it was 35 at the basement laundry sink. But, I told him that a friend had one installed right down the street and it worked fine. I asked him if his pressure could be that much higher and he said it would be the same for the whole street. Anyone have one of these with lower pressure?