Water Pressure Seems Too Low
Mar 10 2010Dear Barry: We bought our home less then a week ago. After moving in, we found the water pressure to be unacceptable. It takes forever to fill the bathtub, but the previous owners had said that they used it all the time. Why did our home inspector say nothing about low water pressure? Lori
Dear Lori: People often mistake low water volume for low pressure. For example, it is possible to have normal or even high pressure and yet have weak flow at the faucets. This often occurs in older homes where corrosion in old galvanized steel pipes restricts the flow, regardless of pressure. Low flow can also be caused by a faulty valve or by water-saving devices in the faucets.
According to the Plumbing Code, water pressure must be at least 15 pounds per square inch (psi) and no more than 80 psi. You should ask your home inspector to come back and review this condition. He should take a pressure reading and evaluate the flow rate at the tub. You should also get an opinion from a licensed plumber.
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Dear Barry:
Here in Ontario it is Code for builders to install a 3/4 in . copper water supply to all homes. It has been that way for over 40 years and most municipalities upgrade these services to the property line during road reconstruction projects. Most home owners do not know what is or was under their lawns for piped services. This information here is free and I often provide it to clients after an inspection. Many complaints of low water flow or low pressure can be resolved by excavating from your basement to the property line and replacing the old 1/2 in. copper or 1/2 in. steel with 3/4 in. copper. Many newer homes have a 3/4 in copper supply into the basement but the plumber and often the water heater installer reduces the 3/4 in. pipe to 1/2 in. at the water heater. Typically this is done without a dielectric fitting thus adding to the short life of the steel water heater itself. Other plumbers simply continue on with the 1/2 in. pipe throughout the rest of the home. All water heater are made with 3/4 supply threaded nipples. The 5 plumbers I spoke with all said they do this to “limit” the water pressure in the rest of the home. When did this set of piping fittings replace plumbing design ?