Do you want to get rid of drain smell for good? A bad drain smell is one of the fastest ways to put customers and staff off a business. Whether it’s coming from kitchen drains, toilet drains, urinal drains, washroom sink drains, shower and changing room drains, floor drains, grease traps or waste pipes, an unpleasant odour tells people your premises aren’t being looked after, even when everything else is spotless.
In a commercial building, drain smells usually have more than one cause. Food waste, fats and grease build up inside kitchen drains, soap scum and hair collect in washrooms and showers, and rarely used floor drains dry out, which lets sewer gases escape through the empty trap. The more people use the space, the faster these problems build up, and the harder they become to fix with a quick pour of disinfectant.
R3 can trace and fix the problem professionally, quickly and with minimal disruption to your business. If you’d rather tackle it in-house or you’re working to a budget, follow our step-by-step DIY guide below.
Step 1: Find the source
Smell each drain in turn, including kitchen, toilet, urinal, washroom sink, shower and floor drains. Rarely used drains are common culprits. The smell is often strongest at one drain, so tracing it first saves treating the whole building. If several drains smell at once, the problem may be deeper in the system.
Step 2: Plan the work and stay safe
Work during a quiet period, close off the area, ventilate it well and wear gloves and eye protection. Check the safety data sheet for every product as part of your COSHH assessment. Never mix cleaning products, as bleach combined with acids or ammonia can release dangerous fumes.
Step 3: Clear the surface build-up
Remove grilles, strainers and covers, then clean off food waste, hair and sludge. Wipe the inside of the drain opening and the overflow hole on sinks, which is often forgotten. Put the waste in the bin rather than rinsing it down the pipe.
Step 4: Flush with hot water
Flush with hot, not boiling, water, as boiling water can damage some plastic pipes. This loosens light build-up before you treat the drain.
Step 5: Treat the drain
In kitchens, use an enzyme or bacterial drain treatment designed for commercial use. It breaks down the film lining the pipe that causes most lingering smells, without harsh chemicals. For washroom and shower drains, use a drain cleaner or deodoriser suited to your pipe type and follow the label. Check the product is safe for your pipes, and avoid chemical openers where splashing is a risk.
Step 6: Allow dwell time
Leave the product for the time stated on the label. This gives it time to break down the build-up rather than washing straight through. Enzyme treatments often work best overnight, so apply them at the end of the day and keep the drain out of use.
Step 7: Scrub and flush
Scrub the accessible part of the drain with a drain brush, then flush with plenty of clean water.
Step 8: Refill dry traps
Every drain has a water trap that blocks sewer gas. In rarely used floor drains, sinks and showers, the water can evaporate and let smells escape. Refill them with clean water and add weekly flushing to your cleaning schedule. For drains that are used very little, a trap seal or primer device slows evaporation.
Step 9: Check urinals and toilets
Clean urinal bowls, traps and strainers regularly, change waterless cartridges on schedule and check around toilet bases for leaks. A toilet that smells after cleaning may have a failing seal.
What if the smell won’t go away?
If the smell comes back after a thorough clean, the cause is probably deeper in the system or needs specialist attention. The most common reasons are:
A blocked or partly blocked pipe: trapped waste sits in the pipe and rots, causing a smell that keeps returning.
A full or poorly maintained grease trap: grease traps need regular emptying by a licensed contractor, and a full one will smell however often the drains are cleaned.
A damaged or leaking pipe: cracks and failed joints can let sewer gas escape.
A faulty vent or trap: poor venting can pull water out of traps and draw smells into the building.
At that point, a professional drain survey or jetting will find and fix the cause rather than masking the smell.
When to call a professional
DIY works for light smells and routine upkeep. For recurring odours, several affected drains, blocked pipes or grease traps, R3 has the equipment and training to find the cause and fix it properly, with minimal disruption to your business.
