What Line Size Should I Choose?
The line size refers to the diameter of the water pipe or tubing that connects to your water meter. Choosing the correct line size is crucial to ensure both efficient water flow and accurate measurement by the water meter.
How to Determine the Line Size:
- Check the Existing Water Meter: If you are replacing a meter, check the size of that meter. Most water meter manufacturers print the size somewhere on the face or register.
Note:
If it says [ 5/8" x 3/4" ]
that is a 3/4" line size...
If it says [ 5/8" x 1/2" ]
that is a 1/2" line size...
the 5/8" refers to an old water meter standard.
- Check Existing Pipes: If you are installing the water meter into an existing pipe, you just need to know what the size of that pipe is. The line size is often marked on the pipes themselves.
- Check Existing Valves & Fittings: Often times the line size is cast into the body of a valve or fitting. Sometimes pipe fittings like T's Elbows, the line size is stamped or otherwise marked on the fitting.
- Measure the Pipe: If the size is NOT marked on the pipe, you must measure the pipe.
BEWARE! The outside diameter (OD) of the pipe is NOT the pipe size!
Use the charts below to determine the line size once you have accurately measured the OD.
In order to measure the OD accurately, you should use a pair of calipers.
| BEST |
BETTER |
GOOD |
DESPERATION |
 |
 |
 |
 |
| Precision calipers |
Large adjustable wrench |
Bar clamp |
Homemade Calipers (use our template) |
| Material |
Nominal Pipe Size (NPS) |
Outer Diameter (OD) (inches) |
|
PVC & CPVC
Schedules 40 & 80 |
1/2" |
0.840" (≈13/16") |
| 3/4" |
1.050" (≈1 1/16") |
| 1" |
1.315" (≈1 5/16") |
| 1 1/4" |
1.660" (≈1 5/8") |
| 1 1/2" |
1.900" (≈1 7/8") |
| 2" |
2.375" (2 3/8") |
| 2 1/2" |
2.875" (2 7/8") |
| 3" |
3.500" (3 1/2") |
| 4" |
4.500" (4 1/2") |
|
| Copper |
1/2" |
0.625" (5/8") |
| 3/4" |
0.875" (7/8") |
| 1" |
1.125" (1 1/8") |
| 1 1/4" |
1.375" (1 3/8") |
| 1 1/2" |
1.625" (1 5/8") |
| 2" |
2.125" (2 1/8") |
| 3" |
3.125" (3 1/8") |
|
| PEX |
1/2" |
0.625" (5/8") |
| 3/4" |
0.875" (7/8") |
| 1" |
1.125" (1 1/8") |
| 1 1/4" |
1.375" (1 3/8") |
| 1 1/2" |
1.625" (1 5/8") |
- Consult a Professional: If you're unsure about the correct line size or if your water meter installation involves complex piping systems, it's advisable to consult a licensed plumber or a water utility professional. They can provide expert guidance based on your specific requirements.
Why Line Size Matters:
-
Water Flow: Choosing the correct line size ensures adequate water flow through your plumbing system. A line that is too small can restrict water flow, leading to low water pressure and potential performance issues.
-
Meter Accuracy: Proper line sizing is essential for accurate water meter readings. Using a line that is too large or too small can affect the meter's ability to measure water consumption accurately.
-
System Efficiency: Correctly sized lines contribute to the overall efficiency of your water distribution system, minimizing energy consumption and reducing the risk of leaks or pressure fluctuations.
Still Unsure?
If you have any doubts or questions about selecting the correct line size for your water meter, don't hesitate to reach out to our customer support team for assistance.