When water line repairs or a water line is needed it may be an opportune time for increasing water pressure. Most property owners assume that because an existing service line is a certain size that the new water line should be the same size. in fact that is usually far from true, and in NYC may actually be a violation of code.
In a relatively large percentage of homes plumbing fixtures have been added over the years. Such as dish washers, clothes washing machines, added sinks or bathrooms, and underground lawn sprinkler systems. Any added usage increases the demand for water volume and water pressure may decline. In addition almost all homes now have water meters which further restrict the flow of water, reducing maximum volume. For these reasons and others when a service line is replaced the new water line should be sized out very carefully, especially if increasing water pressure is one of the goals.
The NYC DEP has a carefully constructed sizing table available to ensure that proper sizes are used when water line repairs are done, following them is vital to increasing water pressure. Always ask a plumbing contractor to verify the correct size, do not take this important step for granted. As an example, simply increasing a water line from 1″ diameter to 1 1/4″ will almost double the volume of water for an additional cost of around $100.00 or $200.00 dollars.
The material cost of increasing the size of a water service line is a small price to pay for increasing water pressure in such a dramatic fashion, which can change your quality of life. Multiple plumbing fixtures should be able to be used simultaneously in a home without any drop in water pressure. If you have ever uttered ‘Don’t flush the toilet I’m in the shower’ you know what low water pressure is all about.
Hand-in-hand with increasing water pressure is verifying that the tap connection on the city water main is adequate and to present code. For most areas of NYC the DEP has accurate tap records. One prominent exception is the old Jamaica Water Supply territory that NYC took over in the 1990’s. Most of the old Jamaica Water area has undersized taps along with water line services that are usually undersized and very sketchy records. For homeowners is this area it is typical for a new tap connection to be needed for increasing water pressure.
A rule of thumb is that most two family homes require an 1 1/4″ water main, three family homes require 1 1/2″. Multi-family home should be sized out using the NYC DEP sizing table for correct sizing. Nobody likes to spend money on water line repairs needlessly, but it is better to do it right the first time with the correct size water service line.