Why do my drains smell so bad?

Nov 1, 2022 | News

If a bad odour is coming from your drains, trust me, you’re not alone. This is a common issue. But, what causes it?

It could be just bacteria or it could be something more dangerous like a sewer gas leak. When a foul smell is coming from your drain, you should do some sleuth work to find the cause.

If you’re asking yourself: “Why do my drains smell so bad?” this list of possible causes may be helpful.


The odour could be caused by something as basic as bacteria or gunk buildup. Take into account the things that go down your drains, like food, hair, and dirt. If those things get stuck in your pipes, it can produce a bad smell. Smells go hand in hand with blockages, so it’s probably a sign that it’s time to have your pipes cleaned.

This will hopefully eliminate the smell and any blockages. In some cases, it’s best to hire a professional drain cleaning service to ensure your drains are cleared correctly. 


If your drain has not been in use lately, you might need to just run the water for a bit and then refill the P-trap to fix the smell. A drain pipe a goose-necked section to stop sewer gas from wafting into your home. If the sink isn’t used, the water in the trap will evaporate. This empty drain causes a smell in your home.

To prevent P-traps from drying out, run a little water in each of your faucets once a month.


Most people don’t know that the drains pipes are connected to a network of vent pipes, which bring fresh air in and allow wastewater gas and odour to leak out. Together with the drains, this is called the DWV (drain-waste-vent) system. Normally, these vertical vent pipes go out through the roof, preferably some distance away from windows and vents.


If there’s a bad smell coming from your basement sump pump, check your main sewer drain line to make sure it’s not running into your sump pump. Some homeowners will have water from the washing machine run into the sump pump, which can build up over time and cause a bad smell.


If fat or grease gets stuck in your kitchen sink drain, it can cause a rotten egg or mold smell when it congeals. You should never pour grease down the drain. Pour two teaspoons of baking soda down drain, then vinegar, followed by boiling water. This will dissolve the gunk, and the hot water will wash it away.


Plumbing experts recommend installing a proper drain trap to prevent sewer smells from coming into your home. If it’s not done, there’s nothing to block the smell from coming into your home. The drain trap would need to be installed by a professional.


Water issues such as sulfates can be the cause of a bad smell. If sulfate-reducing bacteria gets into the hot water heater, it can produce a rotten egg smell.

If you think the cause of the smell is the water itself, you should contact a professional plumber to examine your water pipes and the quality of your water.

Those are seven possible reasons for the bad smell coming from your drains. If the problem persist, you should contact a professional drain cleaning service.

Why use Drain Blasters?

Cutting edge technology

Drain Blasters only works with the latest technology and equipment, using high pressure water-jetting.

Portable equipment

Our portable equipment can be carried into buildings and lifts in order to access those hard to reach places.

Scalable Equipment

Our fleet ranges in capacity and size from 1 to 10 tonne waste removal capacity and drain clearing capabilities, suitable for residential and industrial blockages.


Highly experienced teams

Our teams are made up of highly experienced individuals who are professional and friendly

24/7 Service

We are on call 24/7 to assist in the case of emergencies and short notice service

Competitive Prices

We offer highly competitive pricing while maintaining a high level of service

Our Services

Drain Clearing

Our experienced experts are available around-the-clock and are equipped with the latest drain clearing tools and technology to get the job done fast and effectively.

Liquid Waste Removal

We offer a professional, socially responsible & price effective solution as a leader in liquid waste management.

Septic Tank Cleaning

We specialize in septic tank cleaning and drainage, whereby we pump out and clean the contents of septic tanks.

Grease Trap Cleaning

Our grease trap cleaning process ensures a free flowing drainage system and alleviates odours in your workplace in a systematic, discreet and environmentally friendly manner.

Grease Traps

We proudly install grease traps into restaurants and institutions which require filtration of grease, fats, and oils from their wastewater.

Sewage Removal

We have extensive expertise and experience in resolving sewerage blockages of all sizes, with special care taken to dispose of sewage safely and effectively.

Areas We Service

Drain Blasters services almost all areas across Cape Town and Surrounding Areas

Airport Industria | Athlone | Atlantic Seaboard | Atlantis | Bakoven | Bantry Bay | Bellville | Bergvliet | Bishopscourt | Blackheath | Bloubergstrand | Bo-Kaap | Boland | Bothasig | Brackenfell | Brooklyn | Camps Bay | Capri Village | CBC | Century City | Claremont | Clifton | Clovelly | Constantia | Crawford | Crossroads | Culemborg | Darling | De Waterkant | Devil's Peak Estate | Diep River | Durbanville | Edgemead | Eersteriver | Elsie's River | Epping | Epping 2 | Epping 1 | Fish Hoek | Foreshore | Franschoek | Fresnaye | Gardens | Glencairn | Goodwood | Gordon's Bay | Green Point | Harfield Village | Heathfield | Hout Bay | Imizamo Yethu | Kalk Bay | Kenilworth | Kenwyn | Killarney Gardens | Kirstenhof | Kommetjie | Kraaifontein | Kreupelbosch | Kuils River | Lakeside | Lansdowne | Llandudno | Lotus River | Maitland | Malmesbury | Mamre | Meadowridge | Melkbosstrand | Milnerton | Montague Gardens | Mouille Point | Mowbray | Muizenberg | Ndabeni | Newlands | Noordhoek | Northern Suburbs | Observatory | Ocean View | Oranjezicht | Paarden Island | Paarl | Panorama | Parklands | Parow | Philippi Industrial | Pinelands | Pinelands | Plattekloof | Plumstead | Retreat | Rondebosch | Rondebosch East | Rosebank | Rugby | Sacks Circle | Salt River | Scarborough | Schotsche Kloof | Sea Point | Simon's Town | Somerset West | Southern Suburbs | SouthField | St James | Steenberg | Stellenbosch | Stikland | Strand | Sun Valley | Sunnydale | Table View | Tamboerskloof | Thornton | Three Anchor Bay | Tokai | Vredehoek | Waterfront | Wellington | West Beach | Wetton | Woodstock | Wynberg | Zonnebloem