[LazyPup]

When it is necessary to do a theoretical demand in leu of actual demand figures I find it is always best to inflate the figures slightly to insure the system is adequate.

When designing pipe layouts for single family residential systems it is pretty basic and there are some rules of thumb that apply, however, when designing pipe layouts for multifamily structures or commercial layouts the codes have a series of tables that assign a specific volume demand which is rated in "fixture units". We must then analize each point of demand individually to determine the total fixture units for that area, then determine the size of the branch line required to serve that portion of the structure.

The method of determining supply line size by fixture units is very similar to the method used to compute drain line diameters. In fact, determining drain lines is more critical as an oversized drain line will cause more problems than an undersized one.

I also agree that there appears to be an error with the meter.

It is obvious that the meter was changed, but you still retained the same main line from the street, the same internal distribution piping, and basically the same demand load, so it should be easy for the water company to check billing records for a period of a year or two prior to the installation of the new meter and compare that average to the readings they are getting with the new meter.