Denver Water receives many calls from customers living in older houses with the common complaint of low water pressure. After checking our records and asking additional questions about the nature of the problem, it’s often identified as low flow rather than low pressure. Below is more explanation of the causes, responsibilities and solutions for this type of problem.
A common problem encountered in older homes in Denver (those built in the 1930s and before) is a reduction of flow rate, often misinterpreted as poor pressure. Many residences built before 1900 have half-inch taps and half-inch lead service lines. In later years the common practice switched to 5/8 inch taps and 5/8 inch or ¾ inch galvanized steel service lines. It was not until the 1950s and 60s that ¾ inch taps and ¾ inch copper service lines became standard. The service line is owned and is the responsibility of the property owner.
Over time, mineral deposits accumulate on the interior surface of lead and galvanized service line pipe. This interior accumulation of minerals and corrosion decreases the interior pipe diameter, creates a rough inner surface and also reduces the available area for water flow. All of these contribute to a reduction in flow. The older the pipe, the worse the internal build-up problem and the lower the flow delivery will be. Please note that this internal build up of minerals and corrosion does not pose a health threat.
For most older homes with reduced flow, there are only two solutions: Learn to live with the problem, or replace the service line and tap. The first is not very convenient and the second is very costly. In cases where the customer does not wish to spend the money to replace the service line, switching to water-conserving fixtures (such as low-flow shower heads and faucet aerators) may help.
The best approach is complete replacement of the tap, service, and meter (if necessary) all the way from the main in the street to the residence. It's also important to check the buildup in the plumbing inside the house. A licensed, bonded plumber or contractor should do both types of replacement.
When we respond to a low-pressure complaint, we usually pull the meter to verify that there is adequate flow and pressure to the meter setting. In many cases we find the flow is adequate at the meter pit (or at the inside meter), indicating the problem is corrosion or a blockage after the meter. If we find adequate pressure but low flow at the meter pit, the problem is on the street portion of the service, which is still the owner’s responsibility to replace.
If the house has an inside meter, the owner will need to move it to a meter pit when replacing the service line. Although that also may add to the cost of the repair, it eliminates the inconvenience of having someone available to provide access to the meter for repair, maintenance and periodic checks on the meter.
Questions regarding the size and date of installation of an existing water tap as well as the actual pressure at a specific location may be directed to Denver Water Customer Care at 303-893-2444.
If you do not live in an older home and are experiencing low water pressure, call Denver Water Customer Care at 303-893-2444.