"Understanding Your Home" by Building Inspector Mark Visser
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LONG RUNS TO SECOND FLOOR. WATER SOFTENERS
- There is a pound of pressure lost for every 2.30 feet (70 cm) of vertical water line. To put this in perspective there could be a water pressure drop of 10 psi between the water meter and a second floor showerhead.
- If you add a water softener you could lose another 10 psi.
- On a well system, where the normal pressure is 20 to 60 psi, loosing 20 pounds of pressure in these two scenarios doesn't leave much room for other water demands. Doing the dishes may have to wait!

LOW PRESSURE (water flow) AT ONE FAUCET
If the low pressure is limited to one plumbing outlet the problem is most likely not low water pressure but low water flow due to gummed up faucet. First see if the aerator screen needs cleaning. The aerator is located at the tip of the faucet and can be unscrewed, counter clockwise. If that doesn't restore full flow you may have to replace the faucet.

TESTING THE HOME'S WATER PRESSURE
On a well system, the normal pressure is 20 to 60 psi, city water pressure is normally 50 to 75 psi. If you suspect that the water pressure is too low you can check the static water pressure by threading a water pressure gauge onto any hose bib and turn on the water. The static water pressure is the pressure, anywhere, on the water supply system while all other fixtures are turned off. If the home is on a well and pump system, let the water run till the pump starts running.


Galvanized supply lines rust
from the inside out



What causes Low Water Pressure and how to fix it





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Lead watermain. Galvanized steel plumbing pipes
There are several reasons why you have low water pressure in your home.
If you live in a home that was built prior to 1950s and has still the original plumbing (lead watermain, galvanized supply pipes) you know that low water pressure can be at times a big problem. Low water pressure can make life less pleasant. Small tasks such as doing dishes or taking a shower will take time. Filling the bathtub may take forever. You most likely have learned how to live with the inconveniences. The good news is that water pressure in an older home can be increased.

POSSIBLE REASONS FOR LOW WATER PRESSURE
There could be several reasons for having a low water pressure in the home. It has either always been that way or has gotten worse over a long period of time. The reason for low water pressure could be:
- an undersized watermain to your house
- or your home is located at the end of a municipal system, far away from a municipal pumping or booster station
- you installed an irrigation system that includes backflow prevention
- long runs to second floor bathrooms
- water softener equipment
- lead watermains
- galvanized interior supply lines
- and yes, a partially closed main shut-off valve! I have seen this several times during my 28 years of inspecting homes.






HOW TO INCREASE PRESSURE IN OLDER (pre 1950s) HOMES
- Replace the old lead watermain leading from the street to your house.
- Replace all galvanized supply lines.
- Adding a pressure chamber to boost water pressure is pretty straight forward. On the house side of the water meter remove 10 feet (3 m) or more of the feed line and replace it with a 3/4 or 1 inch diameter pipe.

REPLACE THE OLD LEAD WATERMAIN
Lead watermains are very soft and grey in colour. Any scratches show up as a bright silver colour. When you tap the pipe it doesn't sound hollow. Galvanized steel watermain have almost the same colour but are much harder and cannot be easily scratched.
Lead watermains can also be identified by a large ball type connection at the joints, see picture. Even today there are still plenty of homes with a lead watermain, especially in older communities.
Replacing the old lead watermain with a copper one is expensive The municipality will pay for the section from the street to the property line. You are responsible for the costs of a new watermain from the property line to the house. This could be expensive if the house is located way back from the road.
Many municipalities have information on their web sites about lead watermains, replacement programs, how it effects your health, how to prepare the water before consumption, replacement programs or low interest loans. If you cannot find the information on the web you are looking for contact your local municipal health department. You can also go to "Lead in our drinking water" for additional information.
WARNING
Lead leached into your drinking supply can lead to serious heath problems. For more information go to "Lead in our drinking water"

REPLACING THE OLD GALVANIZED HOT AND COLD WATER SUPPLY LINES
Galvanized steel pipes were used until the mid 1950s and have a maximum life span of around 40 years. The rust inside those old pipes is ruining all of your expensive appliances such as your dishwasher, water heater, and washing machine. 
They are no longer an acceptable material for potable water as it rusts from the inside out. Older pipes partially blocked by corrosion are often the cause for low water pressure. To increase water pressure in an older home all galvanized water supply lines should be replaced. However, due to accessibility or financial reasons this was not always done. As a former building inspector I have seen many homes where only the easily accessible horizontal sections of pipe in the basement had been replaced with copper pipes while the vertical runs were still galvanized steel. In some cases I noticed that only the hot water pipes had been replaced (hot water picks up more lead than cold) which doesn't make economical sense as hot and cold water supply lines usually run side by side. Both should have been replaced at the same time.

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