# What Size Water Supply Line For 300 Ft Distance: The Ultimate Guide

What size water supply line will you need for a 300 ft. distance from your house? It’s a tricky question. Typically, the water supply line size should be 1 1/2 inches.

The water line’s size is crucial to provide a sufficient amount of water to the residents of a building. So, if you don’t know the size, then you will be in big trouble.

Also, it plays a vital role in doing a DIY project of water supply line installation. Don’t worry! Our researchers have left no stone unturned to find you the proper guidelines for **what size water supply line for 300 ft**. It will help you to easily install a water supply line at a 300 ft distance from your house. Check the entire article to know more.

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## What Size Water Supply Line For 300 Ft Distance You Need?

Due to the intermittent use of the fixtures in a water supply system, it can be difficult to predict the size of the supply and service lines. The fixtures’ total theoretical demand should always be compensated with statistically more expected demand.

The proper water supply line’s size, also known as the water service line, is determined by 3 key factors. The 3 key factors are given below:

- A sum of all the plumbing fixture units in a building
- The distance from the main meter to the farthest plumbing fixture
- The sizing requirements of the residential and commercial buildings

Before determining the size of the water supply line, you need to think about the pressure of the water in your house first. Your local building code might be able to give you a fixture unit. You can see how many cubic feet of water each appliance or plumbing fixture uses each minute with this fixture unit. Using this information, you can choose the right water supply line type and size for your project.

In Florida, a 1-inch PVC water supply line could supply water to a home with seven bathrooms at a water pressure of 50 PSI. However, the water pressure should not cross 80 PSI. Water pressure of more than 80 PSI must be decreased using a pressure reducer.

Also, our researchers have found out that many people think a 1 1/4 inches plastic water supply line is good for a 300 ft distance from your house. However, it is not true. It is recommended that you should use a 1 1/2 inches supply line for a 300 ft distance from your house. An expert homeowner said regarding this in a forum on Plumbing Forum,

“In many areas, 1 1/4” is a “forgotten” size and there is not a lot of demand for it. We would normally use 1 1/2” for your application.”

NYC plumber Paul R Balkan says,

“The larger the diameter of the supply pipes the less of a pressure drop will occur as more and more plumbing fixture are used at the same time.”

Also, according to our researchers, a 3/4 inches copper water supply line is ideal for a 300 ft distance. Another option is a 1-inch PEX water supply line, which is quite small to install on your home for a 300 ft distance from your house.

Another homeowner named Jimmy said in the same Plumbing Forum,

“Remember that 1” pex has an id closer to that of 3/4” copper. Using a max. gpm of 15 gpm estimated, your 1” pex could have 15 to 20 PSI pressure loss over 300 feet. Stay with 1 1/4” poly or sch.”

The advantage of using the PEX water supply line is you can buy it in 100’ rolls. The water supply line needs to be a minimum of 40 inches under the ground. The area where the water supply line is situated has to be marked, and there should be nothing more than the water supply line.

You can also dig the ground 48 inches deep and use a black color plastic water supply line with 1.5 inches diameter. This water supply line is inexpensive and can be used at a 300 ft distance from the main water line.

A homeowner named Terry said in a forum on Terry Love forum,

“

The 1” is the minimum size you will want to go with for 300 feet on a one bath home. You can go larger and it doesn’t hurt anything.”

## You Can Check the Below Video to Learn More About the Water Supply line Sizing

## Frequently Asked Questions (FAQs)

### How big should water supply lines be?

The ideal water supply line size for less than 100 feet distance from the house should be 1 inch. An 8 inches diameter water supply line can supply water to hundreds of homes. For 300 feet distance from the house, the water supply line should be 1 1/2 inches. Also, a 1 1/4 inches pipe can be used as a water supply line. Keep in mind that bigger diameter supply water lines produce less friction.

### How do I calculate water line size?

To calculate the water line size, you need to know 4 key factors. These are total plumbing fixture units, the height of the highest plumbing fixture, the distance to the furthest fixture, and water pressure. After knowing them, you can use the 75% method to calculate the water line size. If the fixture receives both hot and cold water, multiply the total fixture unit by 0.75. The outcome number is every water line’s size.

### How many fixtures can I put on a 3/4 water line?

You should put 2 fixtures on a 3/4 inches water line. If you put more than 2 fixtures on a single 3/4 inches water line, then you will face water pressure problems. We found out many people connected 19 plumbing fixtures to a 3/4 inches water line. These include 4 showers, 2 outside spigots, 6 sinks, a dishwasher, 3 toilets, a fridge, and more. They have faced a lot of water pressure problems after that.

### Does a larger pipe increase water flow?

The answer to this question is both yes and no. After deep research, our researchers have found out that larger pipes have a slower flow of water. The amount of possible flow of water through the water line will increase with larger pipes. However, if the water is not up to that required flow rate, it will not raise water pressure.

### Is 3/4 PEX big enough for the main water line?

Yes, a 3/4 inches PEX pipe is big enough for the main water line. It is a standard size for water supply lines with PEX pipe. Another option for the main water line is a 1/2 inches PEX pipe. Larger PEX pipes, such as 3/4 inches and 1/2 inches, will hold more water. We have also found out that a 3/4 inches PEX pipe is good for the main water line of smaller homes.

## Final Words

If the distance between your house and the main water line is 300 ft, then you need to know what size is perfect for the water supply line. When you search for it on the internet, you will see suggestions ranging from 1 1/2 inches, 1 inch, and 1 1/4 inches. You might get confused after seeing all these suggestions and may not make the right choice.

We are hopeful that this article has helped you to remove that confusion, and now you know the answer to “**What size water supply line for 300 ft**?” According to us, 1 1/2 inches is the perfect size for a water supply line for a 300 ft distance from the main water line. Nevertheless, the final choice is yours, and we hope that you will make the right decision.

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