What Size PEX Pipe Do I Need for My House?

Have you ever wondered what size PEX pipe you need for your home? We’ll show you how to determine the right size PEX pipe for your needs.

Checkout this video:


There are many factors to consider when determining the size of PEX pipe that you will need for your home. The most important factor is the desired water flow rate. This will determine the maximum diameter of the PEX pipe that you will need. Other important factors include the length of the run, the number of fittings, and the type of water pressure system in your home.

Determining the right size PEX pipe

The size of the PEX pipe that you need for your house depends on a few factors. The first factor is the size of your home. The second factor is the number of bathrooms in your home. The third factor is the number of occupants in your home. The fourth factor is the water pressure in your area.

Consider the length of the run

In general, you would use a different size pipe for each situation:
-For long runs (more than 500′), 3/4″ pipe is typically used.
-For short runs (less than 150′), 1/2″ pipe is typically used.
-For very short runs (less than 35′), 3/8″ pipe may be used.

You should also consider the number of fixtures that will be connected to the pipe. For example, if you are using 1/2″ pipe and have three fixtures, each with a flow rate of 1 gallon per minute, you would need a 2 gallon per minute flow rate for the entire system. In this case, you would need to upgrade to 3/4″ pipe.

Consider the number of fixtures

The first thing you need to do when determining the size of your PEX pipe is to count the number of fixtures in your home. A fixture, for our purposes, is any point where water enters your home, such as a sink, a toilet or a showerhead. You should also count any appliances that use water, such as a washing machine or dishwasher.

##Heading:Estimate the flow rate
The second factor you need to take into account is the flow rate of each fixture. The flow rate is the amount of water that flows out of a fixture in a certain amount of time. For example, a showerhead might have a flow rate of 2 gallons per minute (gpm). To find the flow rate of your fixtures, you can either consult the manufacturer’s documentation or measure it yourself.

To measure the flow rate yourself, simply timed how long it takes to fill up a gallon-sized container with water from the fixture. For example, if it takes 30 seconds to fill up the container, then the flow rate is 2 gpm.

##Heading: Calculate your needs
Once you know the number of fixtures and their respective flow rates, you can calculate the size of pipe you need using the following formula:
PEX pipe size = (flow rate x 60) / 8
So, for our example above with two fixtures with a flow rate of 2 gpm each, we would need a  3/4″ pipe.

(2 x 60) / 8 = 15/2 = 3/4″

Consider the water pressure

Water pressure in a home can be measured by turning on a water faucet at full force and measuring the pressure with a pressure gauge. The average water pressure coming into a home is between 40 and 50 psi. However, some homes have pressures that range from 60 to 80 psi.

PEX pipe is available in sizes from 3/8-inch to 1-inch in diameter. For most homes, the main water line coming into the house has a diameter of 3/4 inches. From there, smaller PEX pipes branch off to supply different fixtures and appliances throughout the house.

The first step in determining what size PEX pipe you need for your house is to check the water pressure. If it’s within the normal range of 40 to 50 psi, then you can use the following formula to calculate the appropriate size pipe:

Water pressure (psi) x Pipe length (ft) / Water demand (gal/min) = Pipe size in inches

For example, if you have a water pressure of 45 psi and you need to run a 1/2-inch line 50 feet long to supply a bathroom faucet that has a demand of 0.5 gallons per minute:

45 x 50 / 0.5 = 4500 / 0.5 = 9000 / 0.5 = 18000 / 0.5 = 36000 / 0.5 = 72000 / 0.5 = 144000


So, what size PEX pipe do you need for your house? The answer depends on a few factors, but in general, you’ll need a larger diameter pipe for more water pressure and a smaller diameter pipe for less water pressure. Ultimately, the decision comes down to personal preference and the specific needs of your home.