How to Get Permission to Build Inside a Floodplain in South Africa

There is no single permit for building in a floodplain. Depending on the site and the works, you may need approvals from three different authorities: the municipality (land use, stormwater and building plans), the Department of Water and Sanitation (a water use authorisation) and the provincial environment department (environmental authorisation). Each asks for overlapping evidence, and each runs on its own clock. The first question is whether the municipality allows the development at all.

Planning to build in or next to a floodplain? We prepare the floodline and flood assessment every one of these approvals relies on, and the water use application.

Floodline determination

Step 1: Map the lines

Every approval depends on where the site sits relative to:

• the 1:50 and 1:100-year floodlines;
• the riparian edge and any wetlands, which with the floodline define the regulated area of the watercourse;
• 32 m from the edge of the watercourse, which can trigger environmental authorisation;
• the municipality’s own buffers.

Our post on the lines that control building near a river explains each one. Without a floodline, nothing else can be scoped.

Step 2: Check whether the municipality allows it

Some municipalities bar development in parts of the floodplain outright:

Municipality	Rule	Source
Cape Town	No new rights, and no exercising of existing rights, in the high hazard zone; formal residential development not permitted below the 1:50-year line; filling not permitted below the 1:50-year line	Floodplain and River Corridor Management Policy 2009
Johannesburg	No development within the area flooded by a 1:100-year flood, or within the riparian zone plus a buffer of 30, 32 or 50 m, whichever is greater	Land Use Scheme 2018 (2025 review), cl 50(3)(a)
Msunduzi (Pietermaritzburg)	No habitable buildings within the 1:50-year floodline	Single Land Use Scheme 2024, cl 5.43
Nelson Mandela Bay	The Municipality may prohibit buildings, or set conditions, within the 50- to 100-year floodline	Land Use Scheme 2023, cl 56
George	May refuse new permanent residential, commercial or industrial development under the 50-year floodline	Stormwater By-law 2023, s26(4)(c)
Polokwane	No building on land likely to flood once in 100 years without approval; floodline certified by a registered professional engineer	Integrated Land Use Scheme 2022, cl 13
Mbombela	No building below the 1:100-year line unless the City approves the construction method	Land Use Scheme 2019, cl 5.17.2(d)

Where the scheme allows development on conditions, the conditions usually cover floor levels, an engineer’s certificate that flood levels elsewhere will not rise, and sometimes a restriction registered against the title.

Step 3: The approvals, and how long each takes

Approval	Authority	When you need it	Statutory timeframe
Land use application (rezoning, subdivision, consent use, departure)	Municipality	Where the development needs new or changed rights; many municipalities require a floodline certificate with it	Set by each municipality’s planning by-law
Stormwater consent or permit	Municipality	Cape Town and eThekwini: any activity that may raise flood levels; Johannesburg: major developments, clearing in a floodplain, berms	Case by case
Water use registration under the General Authorisation	Department of Water and Sanitation	Work in the regulated area of a watercourse rated Low risk on the risk matrix. A single residential house (with any French drain or conservancy tank at least 100 m from a watercourse) needs registration but no risk matrix	Confirmation within 30 working days of the Department accepting that the submission meets all the notice’s requirements (GN 4167, cl 7(7)(b))
Water use licence	Department of Water and Sanitation	Medium or High risk work, or work the General Authorisation excludes (such as anything that stores water)	Up to 300 days under the 2017 regulations, excluding 15 December to 5 January. The Department said in 2021 that complete applications lodged from April 2021 would be finalised within 90 days
Environmental authorisation (basic assessment)	Usually the provincial environment department; sometimes the national department	Listed activities such as structures of 100 m² or more within 32 m of a watercourse (outside urban areas and existing road reserves), or moving more than 10 m³ in one	Report due within 90 days of the application, or 140 days if a second round of public participation is needed; decision within 107 days of receiving the report; at least 30 days of public participation
Building plans	Municipality	Every building, other than minor building work the municipality exempts	30 days for buildings under 500 m², 60 days for 500 m² or larger (Building Standards Act, s7(1))

These run partly in parallel, but the water use and environmental approvals usually take longest, and a municipality may ask to see them before it approves building plans. Our guide to every law that applies to a site near a river sets out what triggers each.

What every application needs

The same engineering evidence supports all of them:

• The floodline, pre- and post-development. See pre- vs post-development floodlines.
• The effect on others: a difference map showing the change in flood level and velocity at neighbouring boundaries. See will my development flood my neighbours?
• Floor and platform levels with the freeboard the municipality requires. See freeboard.
• Compensatory storage where fill is placed in the floodplain. See filling in a floodplain.
• The DWS risk matrix, completed by a SACNASP-registered professional, for work in the regulated area.
• A stormwater management plan where the municipality requires attenuation.

The order that saves time

1. Commission the floodline and the riparian delineation.
2. Confirm with the municipality what it will allow, before the layout is fixed.
3. Design the layout around the lines, keeping buildings and fill out of the hazard zones where possible.
4. Lodge the water use and environmental applications early; they take longest.
5. Submit the land use application and building plans with the engineering evidence attached.

See our floodline determination and water use licence services, or send us the site details and we will tell you which approvals apply.

This post explains the documents listed below. It is not legal advice; requirements change and are applied case by case, so confirm them with the relevant authority before relying on them.