Water meter size

Is there any point in having 3/4" water piping in the house if the meter in front of it all is 5/8"?

The size of the meter determines the MAXIMUM water you can get. The size of the piping, and its length determine how much of that you actually receive, and its pressure, due to friction loss. Regardless of the size of the meter, an oversize pipe may deliver more water than a smaller one because of various parameters unique to your requirements.

A 5/8 meter is rated to supply all the GPM you probably need. Using smaller pipe than 3/4 could cause unacceptable drop in pressure.

https://terrylove.com/watersize.htm


A standard one-bath home with kitchen sink, dishwasher, water heater, clothes-washer, 1.6 tank toilet, lavatory, tub/shower combo and two hose bibs would be counted as 18 fixture units.


Most standard two bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, two 1.6 tank toilet, two lavatories, one shower, one tub/shower combo, and two hose bibs would be counted as 23.5 fixture units.

Most standard three bath homes consisting of kitchen sink, dishwasher, water heater, clothes-washer, three 1.6 tank toilet, four lavatories, two showers, one tub/shower combo, one whirlpool bath and two hose bibs would be counted as 34 fixture units.

Only a one bath home could use a 3/4" water line. (I always install 1" anyway)
A two and three bath would need 1"
And a four both would require 1-1/4"