Drainage contractor — soil, waste and rainwater drainage with correct venting and gradients

Scope

Scope of work

Stacks are sized from the fixture-unit loading, the system type — single-stack or two-pipe — is chosen for the building height and the fixture arrangement, and every trap is protected by venting so its seal is not siphoned. Horizontal runs are laid at the gradient that keeps solids moving, with cleanouts and inspection chambers where the network can be rodded. Rainwater is sized for the roof area and the design rainfall intensity and kept separate from foul drainage to the outfall or the harvesting system. We supply and install the stacks, branches, vents, underground drainage, chambers and connections.

How it is delivered — and what you receive

Under-slab drainage is laid, tested and inspected before the slab is cast, because it cannot be reached afterwards; stacks are tested for leakage and traps checked for seal retention with the fixtures in use. Connections to the municipal sewer or the STP are made with the invert levels verified on site. The client receives the drainage as-built with chamber and invert levels, the test records and the cleanout schedule.

Sources and standards

• IS 1172 (1993 (reaffirmed)) — IS 1172 — Code of Basic Requirements for Water Supply, Drainage and Sanitation. Bureau of Indian Standards. Publisher.Per-capita water requirements and sanitary provisions by building type.
• NBC 2016 Part 9 (2016) — National Building Code of India 2016, Part 9 — Plumbing Services. Bureau of Indian Standards. Publisher.Water supply, drainage and sanitation, and the per-capita demand basis.

Standards are cited to support the technical statements on this page. Where a standard has been revised, the edition shown is the one verified at the time of review; the edition in force for a project is the one the authority applies.

Before you ask us to quote: the Plumbing buyer's guide lists what to have ready, what drives cost and timeline, and the approvals that usually apply.