Stormwater Drainage for Homes: Gutters, Downpipes, Soakaways and Site Runoff
Guide Type: Technical guide
Plan roof and site stormwater properly: gutters, downpipes, levels, channels, soakaways, municipal connections and water kept away from foundations.
Quick answer
Stormwater planning begins with the site levels and roof layout. Roof runoff, paving falls, downpipes, channels, collection, discharge and overflow must work together without directing water toward buildings, boundaries or vulnerable ground.
How to compare the options
| Option | Best suited to | Include in the allowance |
|---|---|---|
| Roof runoff system | A roof with planned gutters, downpipes and a defined discharge point. | Gutters, outlets, downpipes, bends, brackets and stormwater connection. |
| Site runoff system | External paving and landscape areas that need managed drainage. | Falls, channels, inlets, pipework, soakaway or approved discharge and reinstatement. |
Cost and planning checklist
- Coordinate roof drainage with external levels and landscaping.
- Confirm the permitted discharge approach with the relevant local authority and site professional.
- Keep maintenance access to inlets and channels.
Use the estimator
Build an early, region-aware allowance in the Price Your Build free estimator. It is a feasibility tool, not a supplier quotation, final design or professional certification.
Related Building Glossary guides
Frequently asked questions
Can stormwater just flow to the boundary?
Do not assume this is acceptable; manage it in accordance with the site design and local requirements.
Why include overflow?
Blocked outlets and extreme rainfall still need a controlled path that avoids damage.
Important
Confirm the final product, scope, installation method, drawings, approvals and professional requirements for the specific site before committing to work.
Source to check
National Building Regulations framework: www.gov.za/documents/national-building-regulations-and-building-standards-act-16-apr-2015-1302