How to Unblock an Outside Drain in South Africa
24 May 2026 · Plumbers On Duty
Quick answer
Stormwater drains (yard gullies, downpipes, channels) usually block from leaves and sand — clear with a garden hose, rod or fingers.
Sewer inspection chambers (the round lid in your driveway or garden) block from grease, wipes and roots. If the chamber is full of sewage, the blockage is between you and the municipal sewer — call a plumber. If the chamber is dry, the blockage is between the house and the chamber — also a plumber for anything below the surface.
Tools you'll need
- Strong rubber gloves (always — sewage carries pathogens)
- Garden hose with a jet nozzle
- Drain rods (Builders, R450–R900 for a set)
- Bucket and old towels
- Eye protection
Step 1: Identify what you're dealing with
| What it is | How to tell |
|---|---|
| Stormwater gully | Square grid near a downpipe or driveway, smells of nothing |
| Sewer inspection chamber | Round concrete or plastic lid (200–600mm), smells of sewage when lifted |
| Yard trap | Small square grate near the kitchen back door, soapy/greasy water |
Step 2: Stormwater drain
Mostly leaves, sand and small debris.
- Lift the grate
- Scoop out solid debris by hand
- Hose down with a jet nozzle until water runs freely
- If still blocked, rod through with drain rods (push, don't pull, to avoid unscrewing)
- For downpipes blocked at the bottom, flush from the top with a hose
Step 3: Sewer inspection chamber
ALWAYS wear gloves and eye protection. Sewage contains E. coli, Hepatitis and other nasties.
- Carefully lift the chamber lid (can be heavy — use a pickaxe or bar)
- Look at the level inside:
- Empty / running clear = blockage is between house and chamber, plumber needed
- Full of sewage = blockage is between chamber and municipal sewer
- If full and overflowing onto your property, it is still your plumber's job in most cases. If sewage is also coming up from a municipal manhole in the road, call the municipality.
Step 4: Rodding a sewer line
If you're confident, you can try rodding:
- Feed rods into the inspection chamber, in the direction of the blockage (usually toward the street)
- Screw rods together as you go — always tighten clockwise
- Push and rotate clockwise; pulling back against the threads can leave a rod stuck in the pipe forever
- When water suddenly drains, you've broken through
If you're not confident, stop — a stuck rod adds R3,000+ to the eventual plumber bill.
Municipal contacts when sewage is in the street
| Municipality | Number |
|---|---|
| Johannesburg (Joburg Water) | 0860 56 28 74 |
| Cape Town | 0860 103 089 |
| eThekwini (Durban) | 080 131 3013 |
| Tshwane (Pretoria) | 012 358 9999 |
| Ekurhuleni | 0860 543 000 |
| Nelson Mandela Bay | 080 020 5050 |
Get a reference number — without one, follow-up is impossible.
Common causes outside
- Tree roots in clay or asbestos pipes (very common in older Joburg, Cape Town and PE suburbs)
- Wet wipes — single biggest cause of main-drain blockages globally
- Fats from kitchen sinks congealing in cold underground pipes
- Collapsed pipe from settlement, vehicles parking over a shallow drain, or tree-root damage
- Sand from washing yard tools in an outside trough