Building Near a River in South Africa: Every Law That Applies to Your Site

At least eight national laws can apply to a site next to a river in South Africa. Which ones apply depends on what you are doing: establishing a township, building, crossing or altering the watercourse, mining, building a dam, developing near the coast or farming. Most projects need more than one approval, and each comes from a different authority.

This guide sets out each law, what triggers it, what you need and who decides, with links to the official documents at the end. Municipal rules sit on top of all of them and are covered in the last section.

Planning work near a river and not sure which approvals you need? We start with the floodline, because it defines several of the other boundaries, and map the approvals around it.

Floodline determination

Which law applies to what

What you are doing	Law	What you need	Who decides
Establishing a township, rezoning or subdividing	National Water Act s144; municipal land use scheme	The 1:100-year floodline on the layout plan; often a floodline certificate	Municipality
Building or extending	Building Standards Act s7 and s10; regulation R1	Approved building plans; stormwater disposal	Municipality (building control)
Any work in or near a watercourse	National Water Act s21(c) and (i); GN 4167	Registration under the General Authorisation, or a water use licence	Department of Water and Sanitation
Structures of 100 m² or more within 32 m of a watercourse, or moving more than 10 m³ in one	NEMA EIA Regulations, Listing Notice 1	Environmental authorisation	Provincial environment department
Mining near a watercourse	GN 704	Infrastructure outside set floodlines and distances, or an exemption	Department of Water and Sanitation
Building or owning a large dam	National Water Act Chapter 12; Dam Safety Regulations	Classification, registration and safety evaluations	DWS Dam Safety Office
Developing near the coast	Integrated Coastal Management Act	Development outside coastal management lines, or on conditions	Province and municipality
Cultivating next to a river or wetland	Conservation of Agricultural Resources Act	Written permission	CARA executive officer

1. Townships, rezoning and subdivision: section 144

Section 144 of the National Water Act is the reason most floodlines are drawn:

“no person may establish a township unless the layout plan shows, in a form acceptable to the local authority concerned, lines indicating the maximum level likely to be reached by floodwaters on average once in every 100 years.”

It applies to township establishment, but municipalities extend it to other applications through their land use schemes and planning by-laws. Tshwane’s Land Use Scheme 2024 requires 1:50 and 1:100-year floodline certification by a professional engineer for any application the City specifies. Polokwane requires both lines certified on the layout plan, not more than three years old. Johannesburg’s Land Use Scheme permits no development within the 1:100-year flood area or the riparian zone plus a buffer.

The Spatial Planning and Land Use Management Act (SPLUMA) never mentions floods, but section 42(2) requires a municipal planning tribunal considering an application that affects the environment to “ensure compliance with environmental legislation”. That is how the other laws in this guide reach a planning decision. Our post on rezoning and subdivision covers the sequence.

What section 144 does not do: it does not say who determines the floodline, and it does not ban building below it. Those rules come from municipalities.

2. Building plans: the Building Standards Act

The National Building Regulations and Building Standards Act gives municipalities two flood powers:

• Section 7(1)(b) requires the municipality to refuse plans for a building that “will probably or in fact be dangerous to life or property”.
• Section 10(1)(b) applies where a building is to be erected “on a site which is subject to flooding”: the municipality may prohibit the work, or allow it only on conditions it sets.

Regulation R1 adds a stormwater duty on every site: “The owner of any site shall provide suitable means for the control and disposal of accumulated stormwater which may run off from any earthworks, building or paving.” Compliance with SANS 10400-R is deemed to satisfy it, but the municipality may require a rational design by a competent person. Our post on SANS 10400-H and flood risk explains how these fit together, and what happens if you build inside a floodline covers the consequences.

3. Work in or near a watercourse: section 21(c) and (i)

Section 21(c) covers “impeding or diverting the flow of water in a watercourse” and section 21(i) covers “altering the bed, banks, course or characteristics of a watercourse”. Culverts, bridges, pipelines, outfalls and bank protection all usually trigger one or both.

The General Authorisation for these uses is GN 4167 of 8 December 2023, which superseded GN 509 of 2016. It applies inside the regulated area of a watercourse: the 1:100-year floodline or the riparian edge, whichever is further from the middle of the watercourse; otherwise 100 m from the edge of the watercourse; and 500 m around a wetland or pan.

The DWS risk matrix, completed by a SACNASP-registered professional, decides the route. Low risk can be registered under the General Authorisation; Medium or High needs a full water use licence. Some work is excluded from the General Authorisation regardless of risk, including works that store water and water or wastewater treatment works. Work may start only once DWS has issued a registration letter. Our post on crossing a watercourse covers the process.

4. Environmental authorisation: the 32 m trigger

Listing Notice 1 of the NEMA EIA Regulations lists the development of structures with a footprint of 100 m² or more (and dams or weirs over 100 m²) within a watercourse, in front of a development setback, or “if no development setback exists, within 32 metres of a watercourse, measured from the edge of a watercourse” (activity 12). It excludes development within an urban area and within existing road and railway reserves.

Activity 19 separately lists moving more than 10 m³ of material into or out of a watercourse, with no urban exclusion. In listed sensitive areas, Listing Notice 3 lowers the footprint threshold to 10 m². The competent authority is normally the provincial environment department.

The 32 m distance is a trigger for environmental authorisation, not a no-build buffer. Our post on the lines that control building near a river compares it with the floodline, the regulated area and municipal buffers.

5. Mines: GN 704

The regulations on the use of water for mining (GN 704 of 1999) set floodline limits for mines. Regulation 4 keeps residue deposits, dams and reservoirs out of the 1:100-year floodline and 100 m from any watercourse, and mining or prospecting out of the 1:50-year floodline and 100 m from any watercourse, “whichever is the greatest”. Regulation 6 requires clean and dirty water systems that are not “likely to spill into” each other more than once in 50 years, and a minimum freeboard of 0.8 m on dirty water dams. The Minister may grant exemptions in writing (regulation 3).

See our mine water management service.

6. Dams: the Dam Safety Regulations

A dam is a “dam with a safety risk” under the National Water Act if it can hold more than 50 000 m³ and has a wall higher than 5 m. The Dam Safety Regulations (GN R139 of 2012) classify such dams by size and hazard into Categories I to III. Category II and III dams need an approved professional person, regular safety evaluations, and an emergency preparedness plan with inundation maps of the areas that would flood if the dam failed. Tailings dams are included. In November 2024 DWS called on owners of unregistered dams with a safety risk to register them.

See our dam safety evaluation and dam break analysis services.

7. The coast: the Integrated Coastal Management Act

Under the Integrated Coastal Management Act, the provincial MEC sets coastal management lines to protect public property, private property and public safety, and municipalities must show them in their zoning schemes (section 25). The coastal protection zone includes land that would be flooded by a 1:100-year flood or storm event. Coastal management lines have been delineated for parts of the Western Cape; Buffalo City’s coastal management programme says none have been delineated there yet.

8. Farms: the Conservation of Agricultural Resources Act

The regulations under the Conservation of Agricultural Resources Act define a watercourse’s “flood area” by the 1:10-year flood. Without written permission from the executive officer, no land user may cultivate land within the flood area or within 10 m of it, or drain or cultivate a vlei, marsh or water sponge. Land already cultivated before the regulations started is exempt.

Municipal rules sit on top

Municipal land use schemes, stormwater by-laws and floodplain policies add their own requirements, and they differ widely:

• Cape Town has the most detailed floodplain policy in the country: floodlines drawn on the energy level, floors above the 1:100-year level, and buffers of 10 to 40 m from the top of bank.
• Johannesburg’s stormwater by-law requires documents for work within 100 m of a watercourse centre line to be prepared by a professional engineer approved by the Johannesburg Roads Agency.
• eThekwini requires attenuation for the 1:10, 1:50 and 1:100-year floods, and is revising its floodlines after floods that exceeded the 1:100-year event.

Our guide on how to check if a property is in a floodline lists where each municipality publishes its flood information.

Municipalities also carry their own duty under section 53 of the Disaster Management Act: each must assess and map the disaster risks in its area, including expected climate change impacts. The Climate Change Act of 2024 adds a further assessment duty for metros and districts in section 17, but that section had not come into force as of October 2026.

Laws change

These rules move. GN 4167 replaced GN 509 in 2023, Johannesburg’s revised land use scheme came into operation on 1 July 2026, and a National Water Amendment Bill is before Parliament. We re-check the documents behind this guide regularly; the date at the top shows when it was last updated.

Where to start

On most sites near a river, the floodline comes first, because it defines the regulated area of the watercourse and many municipal setbacks. With the floodline mapped, the other approvals can be scoped in parallel instead of discovered one at a time.

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

This guide explains the documents listed below. Requirements change and are applied case by case, so confirm them with the relevant authority before relying on them.