Domestic water supply and drainage systems

Domestic water supply system

It is the arrangement of pipes, tanks, pumps and fittings that brings water from the public main or a private source (well, spring) to the taps, WCs and appliances of a house, in sufficient quantity, at sufficient pressure and of good quality. Typical parts: service connection with meter, underground sump, pump, overhead tank, distribution pipes with valves, and fixtures.

 Main -> meter -> sump -> pump -> roof tank
                                    |-> kitchen, bath, WC

Types: direct (up-feed), indirect (down-feed from a tank) and combined.

Types of drainage system

Drainage removes sewage and storm water from the building.

1. Combined system: one sewer carries both sewage and storm water. It is cheap and needs only one pipe, but the pipe is large, it overloads in heavy rain, and the treatment plant is overloaded.
2. Separate system: sewage in one pipe and storm water in another. More costly, but the pipes are smaller and the treatment works receive only sewage. Best for new areas.
3. Partially separate system: a small part of the storm water (from roofs and courtyards) goes into the sewer; the rest goes into separate drains.

 Separate system
  house --soil pipe----> sewer -> treatment
  roof/yard --rain pipe-> storm drain -> river

Inside the building: single-stack system (one vented stack for soil and waste), one-pipe system, two-pipe system (separate soil and waste stacks) and the modified one-pipe system. Fixtures have water-seal traps, and inspection chambers are placed at bends and junctions. Outside: drains of vitrified clay, concrete or PVC laid to gradients of 1 in 40 to 1 in 100, connecting to the sewer or septic tank.