Help tackle illegal stormwater-to-sewer headache
27 July 2024
Recent unprecedented rain has seen the City’s dam levels increase to over 99%. This excessive rain has also been putting strain on the sewer and wastewater systems because of the extra stormwater entering the pipes, and contributing to sewer overflows. City teams are continuing with proactive measures, which were also implemented leading up to winter, to help reduce sewer blockages and overflows. Residents can also help prevent stormwater from entering the sewers illegally.
What to know about 1 to 21 July 2024:
- Cape Town dam levels filled by 20% in a week.
- Five rainfall stations in Cape Town show the amount of rain received in July 2024 is two to three times more than the long-term average of 25 to 50 years for July rain.
- There was a spike in Water and Sanitation reports as about 11 000 service requests were recorded for sewer overflows across the city, compared to about 10 000 for the same period in 2023. Foreign items such as waste/refuse, hardened fats, sand, debris and materials, are the main causes of sewer blockages.
- About 18% of these service requests came from Strand, Gugulethu, Bonteheuwel, Philippi, Manenberg, Lotus River, Bishop Lavis, Nyanga, Langa and Wallacedene.
Difference between sewer and stormwater networks:
- Sewers are designed to convey human waste and grey water from domestic and business premises to the Wastewater Treatment Works (WWTWs).
- The stormwater network is usually gravity-fed and designed to convey surface water and rainwater runoff into channels, canals, rivers and vleis to the coast. The piped system has grated covers to prevent waste from entering the system as far as practically possible.
During inclement weather, the City’s Water and Sanitation teams are continuing to proactively monitor the operations at sewer pump stations and wastewater treatment works, and respond to incidents when needed.
Excessive stormwater from the recent heavy rains getting into the sewer network has placed severe strain on the systems and contributed to network overflows.
Due to the peak rain episodes, some WWTWs also experienced increased inflows compared to a usual winter.
Stormwater enters the sewer system:
- Via open or damaged sewer drain manhole covers, which the City replaces when they are reported
- Via illegal stormwater-to-sewer connections on residential and business properties, where water is channelled from roofs, gutters, and paved or hard yard surface areas into sewer drains.
- When residents remove sewer manhole covers to help drain flooded roads, which is not allowed and poses a safety risks for the public such as motor vehicle accidents and injuries, etc.
- Via open or missing manhole covers and rodding eye caps on sewers on private properties which allows surface water to drain into the sewer system
‘We need to work together to help stop stormwater from entering our sewer network as much as possible. Residents are reminded it is illegal to direct stormwater to sewers. The City’s Water Pollution Control team conducts proactive inspections in various areas and collaborates with stakeholders on blitz operations to check that property owners comply with relevant water by-laws.
‘Generally, the sewer system is already dealing with foreign items that are flushed, poured down sinks and drains which cause blockages and overflows which could be avoided. During heavy rain, overflows increase because of illegal dumping of debris, sand, rubble, etc that also wash into the sewer network system, via open manholes where covers have been stolen or damaged.
‘Coupled with this, rainwater also enters via these open manholes and from illegal stormwater-to-sewer cross-connections on properties. All these factors contribute to blockages or reduce the capacity of the pipes to convey wastewater, and damage infrastructure like pump stations, resulting in overflows and flooding.
‘Our committed personnel are still working and responding to urgent calls on the ground, and we anticipate that the heavy rain that is expected starting today will have additional effects.
‘Residents need to play their part by reducing the amount of water entering of sewer network, especially during the rain and to be mindful of what is being flushed, poured down drains and sinks and how they dispose of their waste. Let’s work together to ensure our sewer network functions efficiently which will greatly assist in reducing overflows on our streets especially when it rains. It is equally important that residents assist the City in keeping stormwater gullies and drains clear from debris to proactively prevent localised flooding in their areas,’ said the City’s Mayoral Committee Member for Water and Sanitation, Councillor Zahid Badroodien.
The City mitigates sewer blockages and overflows through proactive measures including:
• Cleaning main sewer pipelines using jetting machines and combination units
• Cleaning sand traps, pump station sumps and wet wells
• Monitoring telemetry alarm systems at pump stations
• Repairing collapsed sewers promptly
• Regularly replacing broken, stolen or damaged manhole covers
• Inspecting and testing the sewer network for illegal stormwater-to-sewer connections
• Conducting public awareness campaigns like "Bin it, Don’t Block it" to educate residents on proper waste disposal
Residents play a critical role to help prevent sewer blockages and overflows:
• Check for illegal stormwater-to-sewer connections and ensure rainwater gutters do not flow into the sewer system to avoid overloading.
• Only flush human waste and toilet paper down the toilet. Anything else blocks the pipes.
• Avoid pouring cooking oils or fats down the kitchen sink. These substances harden and cause blockages.
• Report stolen or broken manhole covers to prevent rainwater and debris from entering the sewer system.
• Report illegal dumping and blocked drains so that it can be cleared and to reduce overflow risks.
• Use the City’s solid waste services for proper waste disposal, or take recyclables, garden greens and builders' rubble to drop-off facilities.
For more tips on preventing sewer blockages, visit www.capetown.gov.za/blocked-sewers
Published by:
City of Cape Town, Media Office
