Water Meter Size

[Gilder]

I need to know how to calculate the size of a water lateral
enterring several different types of buildings in a new development, ie. single family, condo, duplex. I have the fixture demands for each unit but the total required capacity is a lot higher than I need. As an example a single family unit using the fixture count (30 gpm) will need a 1.5" meter. Isn't a single family unit usually supplied with a 3/4" lateral? Is there a weighted fixture demand?

 

[zabrab]

As the combined fixture count increases the probability that all of the fixtures will be in use at the same time decreases. Unless the single family dwellings have an unusually large number of fixtures or have some unusual condition (extremely long service, large vertical difference from the main, in an area of low system pressure, etc.) The “normal” house service line used by the jurisdiction, be 5/8”, 3/4” or 1” will most likely be OK.

For the multi-family and commercial buildings or for the single family dwellings with an unusual condition, follow the sizing procedures and guidance in “Sizing Water Service Lines and Meters” (AWWA Manual M-22).

 

[bimr]

Call up the water utility to find out.

The community where I live is now going with 1 1/2 inch water service as standard for single family residences unsprinklered. Go figure.

Note also that some municipalities are now requiring fire sprinkers in new construction which will also require larger than 3/4 inch water services.

 

[TravisMack]

any residential fire sprinkler system is going to need a 1" meter unless you have great pressure available. The other change is that you typically need a minimum 1-1/4" supply to the sprinkler system riser.