How to Identify Water Meter & Supply Line Size

A critical step in designing an efficient irrigation system is determining how much water you have available, its flow and pressure. Start at the meter. It is usually near the curb buried in a meter box.

To find the meter’s size first look at the dial. Many meters have their size located directly below the gallon count. Sometimes it is stamped on the metal below the dial face. It will be something like ¾” or 1”, in most residential cases. Sometimes it’s not there or so dirty you can’t find it. In that case you have two choices. The easiest might be to simply call your water company and ask. They’ll have it on record. The other option, which is far from accurate but is safe for design, is to determine the size of the pipe leaving the meter and assume the meter is one size smaller. It is fairly common for the meter to be one size smaller than the feed pipe to the house. Typical water meter sizes are: 5/8", 3/4", 1", 1 1/2".

If you can’t read the pipe size on the pipe leaving the meter, don’t worry. DON’T GUESS. Also, don’t lay a ruler across it and use that measurement. If you have PVC you might be lucky enough to see the size printed on the pipe. If not,  or if  it’s not PVC, we have to measure. First, find a piece of string. Now, wrap the string around the pipe and mark the point where the string crosses.  The length between the marks gives you the pipe size.

Step 1: Wrap a length of string around the pipe. Note where the string meets.

Step 2: Measure the string length