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Storm Drainage

Storm Drainage

This chapter establishes requirements for the materials, design, construction, and installation of storm drainage systems for buildings.

P3301 — General

P3301.1 Scope. The provisions of this chapter shall govern the materials, design, construction and installation of storm drainage.

P3302 — Subsoil Drains

P3302.1 Subsoil drains. Subsoil drains shall be open-jointed, horizontally split or perforated pipe conforming to one of the standards listed in Table P3302.1 Such drains shall not be less than 4 inches (102 mm) in diameter. Where the building is subject to backwater, the subsoil drain shall be protected by an accessibly located backwater valve. Subsoil drains shall discharge to a trapped area drain, sump, dry well or approvedlocation above ground. The subsoil sump shall not be required to have either a gas-tight cover or a vent. The sump and pumping system shall comply with Section P3303.

Worked example

Scenario: An architect is designing a new residential foundation in an area with a high water table, requiring a perimeter subsoil drainage system.

Explanation: The subsoil drains must utilize open-jointed, horizontally split, or perforated pipe, conforming to specified standards, and must be at least 4 inches in diameter. If the property is prone to backwater, such as from municipal sewers, the drainage system needs an accessible backwater protection device.

P3303 — Sumps and Pumping Systems

P3303.1 Pumping system. The sump pump, pit and discharge piping shall conform to Sections P3303.1.1 through P3303.1.4.

P3303.1.1 Pump capacity and head. The sump pump shall be of a capacity and head appropriate to anticipated use requirements. P3303.1.2 Sump pit. The sump pit shall not be less than 18 inches (457 mm) in diameter and 24 inches (610 mm) deep, unless otherwise approved. The pit shall be accessible and located so that all drainage flows into the pit by gravity. The sump pit shall be constructed of tile, steel, plastic, cast-iron, concrete or other approved material, with a removable cover adequate to support anticipated loads in the area of use. The pit floor shall be solid and provide permanent support for the pump. P3303.1.3 Electrical. Electrical outlets shall meet the requirements of Chapters 34 through 43. P3303.1.4 Piping. Discharge piping shall meet the requirements of Sections P3002.1 , P3002.2, P3002.3 and P3003. Discharge piping shall include an accessible full flow check valve. Pipe and fittings shall be the same size as, or larger than, pump discharge tapping.

P3303.1.1 Pump capacity and head. The sump pump shall be of a capacity and head appropriate to anticipated use requirements.

P3303.1.2 Sump pit. The sump pit shall not be less than 18 inches (457 mm) in diameter and 24 inches (610 mm) deep, unless otherwise approved. The pit shall be accessible and located so that all drainage flows into the pit by gravity. The sump pit shall be constructed of tile, steel, plastic, cast-iron, concrete or other approved material, with a removable cover adequate to support anticipated loads in the area of use. The pit floor shall be solid and provide permanent support for the pump.

P3303.1.3 Electrical. Electrical outlets shall meet the requirements of Chapters 34 through 43.

P3303.1.4 Piping. Discharge piping shall meet the requirements of Sections P3002.1 , P3002.2, P3002.3 and P3003. Discharge piping shall include an accessible full flow check valve. Pipe and fittings shall be the same size as, or larger than, pump discharge tapping.

A table appears here in the adopted code. Refer to the official source for the full table.

Frequently asked questions

What types of pipes are permissible for subsoil drains?

Subsoil drains must be open-jointed, horizontally split, or perforated pipes that conform to standards listed in Table P3302.1.

What is the minimum diameter required for subsoil drains?

Subsoil drains are required to have a minimum diameter of 4 inches (102 mm).

What special protection is needed for subsoil drains in areas with backwater risk?

If a building is subject to backwater, the subsoil drain must be protected by an accessible device.

Where verbatim source text is shown, it is reproduced from the code as adopted into law by the jurisdiction, sourced from public.resource.org under the government edicts doctrine (see Georgia v. Public.Resource.Org, Inc., 590 U.S. 255 (2020)). This material reflects enacted law and is provided for reference and educational purposes only. It is not legal advice and may not reflect local amendments or the most recently adopted edition. Always verify requirements with the authority having jurisdiction.