What Size Should Your Water Main Be? What Is the Right Size?
June 1, 2021
If you are installing a new water main it is important to make sure that the proper size water main is being installed for your home. It is common to question if the water main is large enough to support the amount of plumbing fixtures in your house. It is also common to question if the water main will provide adequate volume and pressure to your house.
There are several different variables that will assist in determining if you require an upgrade in size. First it is important to understand how the current water pressure is in the house. Is the pressure “good enough”, “terrible” or “perfectly adequate for my family”.
In some scenarios the pressure may be suitable until two people decide to take a shower at the same time, or if someone flushes the toilet while you are showering. Does a situation like this bother you to the point you would like to increase the water volume and pressure. Or is it not that bad of an issue and you can live with it to save the cost of installing the new pipe?
Are you planning a renovation? Are you adding any plumbing fixtures along the lines of a new bathroom, wet bar, sinks etc. All of these additions will impact the required size for your new water main, the more information we have the better we can advise.
Are you purchasing a new home yet do not fully understand the behavior of your water pressure as you have not had a chance to live in the house and really feel it out? In this case we would conduct a complete fixture count throughout the home and calculate the required size that will work best for your house. A few of the details associated with the fixture calculations include linear footage form your house to the city main, gallons per minute and the total number of plumbing fixtures.
If you currently have a lead water main there is a good chance that the inner circumference of the pipe has been reduced as a result of mineral and deposit build up over the years. This alone will restrict the flow of water into your home and in some cases, upgrading from lead to copper may increase the water pressure but this is not a guarantee. It is a lot less common for a build up to occur on the inside of a copper pipe and for the most part the water will run in full.
Another primary component to this calculation is the size of your tap connection. The tap is a valve that connects your water line to the city water main and controls the total volume and pressure that will be released into your pipe. If your tap is undersized and you increase the size of your water main, you will continue to suffer from pressure problems, it is very important to make sure that the tap size is adequate.
If you are experiencing water pressure problems and want to determine how to allow for perfect pressure it is important to consult with a licensed master plumber who will perform a full diagnosis on your home, complete the city water water main sizing table and ultimately let you know exactly what is required to set you up for success.