Plumbing systems are chieflygravity-septic,well-septic,ormeter-sewage. In gravity-septic systems, the supply water arrives from a streamor other surface source located at an elevation above the building andacquires its pressure from gravity, then its waste discharges into a sep-tic/leaching field at least 100 ft downstream from the surface source.
The chiefcriteria for designing a plumbing system are its number of fixtures, numberof fixture units, supply main flow rate, and water pressure at the highestfixture. Initial cost is typically only a portion of projected life-cycle costs.For example, in commercial buildings a fixture’s cost is usually no morethan the cost to maintain it for a few months; thus any features that reducemaintenance costs usually pay for themselves quickly.
Benefit of Service
The essential compo-nent is the fixtures: without them there is no need for the others.
In meter-sewagesystems the supply water enters from a pressurized public main, then thewaste drains into a public sewer system.
waste discharges into a sep-tic/leaching field at least 100 ft downstream from the surface source.