Stormwater disposal and other excess water from your property
Apr 032013

Stormwater Disposal – What the Regulations Say

stormwater 1 Stormwater Disposal

When the heavens open up and flood gardens and roads, you rely on storm water drains to deal with the excess water.

stormwater 2 Stormwater Disposal

The house on the far side of the road was totally flooded during a major downpour. The question is, whether the house was built with sufficient drainage to be able cope with all the storm water.

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, – 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.

This is a drawing from the above SANS that shows how a precast concrete manhole for storm water should be built.Manhole Stormwater DisposalManhole dimensions Stormwater Disposal

  • SANS 10120 – A Code of practice for use with the above, including:
  1. Part 2: Project specification Section LE: Stormwater drainage
  2. Part 3: Guidance for design Section LE: Stormwater drainage
  3. Part 4: Typical schedule of quantities Section LE: Stormwater drainage
  4. Part 5: Contract administration Section LE: Stormwater drainage



  40 Responses to “Stormwater Disposal”

Comments (40)
  1. I stay in Port Elizabeth <
    I am staying in the same house for 12 years, its a panhandle property and my storm water have been draining into my one neighbour property.
    A year ago new owner build on and we have discussed the "drain hole", as he want to put a floor down. I have agreed to put a pipe down at my cost so to control the water and the floor can go on top.
    Two weeks ago I spotted the hole was completely closed of with concrete , spoke to another neighbour and she had the same issue.
    If it rain now my house will be flooded, what to do??

    • Hi Kobus, Here is an extract from the Jhb bye-laws:
      “Where, in the opinion of the Council, it is impracticable for stormwater to be drained from higher lying erven direct to a road, the owner of the lower lying erf shall be obliged to accept and/or permit the passage over the erf of such stormwater: Provided that the owners of any higher lying erven, the stormwater from which is discharged over any lower lying erf, shall be liable to pay a proportionate share of the cost of any pipe line or drain which the owner of such lower lying erf may find necessary to lay or construct for the purpose of conducting the water so discharged over the erf”
      All the municipalities will follow the same bye-laws, so PE wil be the same. You can call the local building inspector and report your neighbour for violating the law.

  2. Hi Penny, I am in a complex and adjacent stand is being developed. It has a close to 60% coverage ratio and I guess about 40% of the remaining land will be paved. The developer has informed me that approx 2/3 of storm-water will be directed to the road via gutters etc. The stand slopes back from the road and, for last 1/3, the developer plans to channel any overflow into adjacent stands including mine. Mine may be marginally lower (a couple of cms) at the boundary, but that is the low point of my stand so storm water could pool up to an estimated 15 cm. I have asked the developer to use french drains etc to improve the stand’s water carrying capacity but have not met any enthusiasm.
    Our suburbs by-laws do indicate that a lower lying stand should take overflow with the higher stand contributing to the cost of any extra drainage requirements on the lower stand.
    Does ‘lower’ mean lower at the boundary or lower on average than the other stand’s boundary?
    Does of the owner, have a unilateral right to make a drainage hole in my wall?
    How far does the owner have an obligation to mitigate storm water run off via, e.g. french drains?
    Is there any guidance on what ‘contribute’ means?
    Lastly, what are my obligations?
    I’d appreciate your suggestions and guidance. Thanks v much for your help

    • Peter, I would think that “lower” means lower anywhere or overall. i.e. Parts could be even lower than on the boundary – or higher on the other side.
      Nobody has the right to make a drainage hole in your wall without your permission.
      But you probably need a lawyer to do a proper interpretation of the bylaws. You might also call the SA Institute of Plumbing (you’ll find regional contact numbers on their website) and ask to speak to one of their committee members who can advise you. In addition to plumbing and drainage issues detailed in SANS 10400 (the National Building Regulations) there are a number of other Standards that deal with drainage.

      • Peter, IOPSA’s technical advisor, Martin Coetzee (who works for Cobra Watertech) is incredibly knowledgable. Why not give him a call? Or ask Iopsa to pass on your message and get him to call you. Good luck

  3. Hi , I am currently renting business premises and have been told that this building might be illegal as it has storm water manhole covers on the floor . Anyone know how i can find out more about the legality of this ?

    • Jeff you can either ask a qualified and registered plumber to inspect (and pay his fee), or ask the local authority to send someone out to inspect. The latter would probably be the best bet because they are ultimately the people who will take action if there are illegal elements in the building.

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