Stormwater Disposal – What the Regulations Say
Property owners are responsible for the removal of storm water from their property. They may NOT simply discharge excess water onto adjacent land or into the street unless this is permitted by neighbors and/or the local council or municipality.
SANS 10400: Part R Stormwater Disposal
The law is very clear on the issue of storm water disposal, although sites used exclusively for “dwelling houses” are not as carefully controlled as larger buildings.
Note that a dwelling house is (in terms of the legislation) a single dwelling unit and any garage and other domestic outbuildings that are situated on the site. A dwelling unit contains one or more habitable rooms and it provided with both cooking facilities and adequate sanitary facilities.
Part R of the law states: “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.”
The legislation also states that the “means of stormwater disposal” used may be addition to, or in combination with any drainage that may be required in terms of F4(2). SANS 10400: Part F Site Operations is described in more detail in the section on site operations which you will find HERE. The relevant section – 4(2) – is also discussed below.
These legal requirements will be “deemed to be satisfied” if the stormwater is provided in accordance with SANS 10400-R (the SANS drawn up by the SABS for “The application of the National Building Relations”, Part R), which is available from the SABS (- CLICK HERE -) for R147 + VAT.
The SANS deals with all types of storm water disposal, including rain water from gutters, downpipes, roofs, and paving, and any other excess water that may accumulate on the property.
In addition, the legislation states that it is the right of the local authority to demand that storm water disposal is provided in accordance with “an acceptable rational design prepared by an approved competent person” (the concept of a competent person is discussed in some detail on our sister site, ownerbuilding.co.za – CLICK HERE for the link to the relevant article). So if your local authority is of the opinion that a qualified person should design a stormwater system for your property they must notify you (or the owner of the property) and explain their reasons in writing, and demand that plans and particulars of “a complete stormwater control and disposal installation” for the site and any buildings on it, are submitted for approval.
The law also states that the regulations should not be interpreted specifically as requiring roof gutters and downpipes if another suitable means of drainage has been provided to remove or disperse rainwater from the roof of the building. There are alternatives that architects sometimes prefer.
Ultimately, all drainage must be shown on plans submitted to the local authority, and it is up to the local authority to decide whether these are suitable and adequate for each individual site.
SANS 10400: Part F Site Operations F4(2)
Part F4 deals with preparation of a site that is to be built on. Point (2) states that when a building is to be erected on a site that is waterlogged or saturated with water, or where any building is going to be situated so that water will drain naturally towards it, drainage must be provided to direct the water away from the site or building, to a storm water drain, or somewhere that it can be disposed of in some other safe and approved manner.
SANS 10400: Part L Roofs
This part of SANS 10400 is dealt with elsewhere on this site – CLICK HERE for the link.
Waterproofing and runoff are dealt with in some detail in the relevant SANS for The application of the National Building Regulations.
Other SANS that deal with Stormwater Drainage
Additional SANS that deal with storm water drains and gullies are intended for the use of civil engineering construction and include:
- SANS 1200 LE – Standardized specification for civil engineering construction Section LE: Stormwater drainage.
- SANS 10120 – A Code of practice for use with the above, including:
- Part 2: Project specification Section LE: Stormwater drainage
- Part 3: Guidance for design Section LE: Stormwater drainage
- Part 4: Typical schedule of quantities Section LE: Stormwater drainage
- Part 5: Contract administration Section LE: Stormwater drainage