Customers notice a drain smell before you do. Here is how to find which drain it comes from, cheapest check first.
📍 We serve KL, Selangor & Putrajaya.
A drain smell in a restaurant, cafe or retail unit usually comes from one of five places: a grease trap that is overdue for emptying, floor traps under equipment that have dried out, grease-coated drain lines fermenting between services, a missing or blocked vent that lets traps get sucked dry, or the building's shared sewer line. Find the source before paying for the fix: refilling dry traps costs nothing, while ClickBina's published market estimates put an under-sink grease trap clean at RM150 – RM400 per service and grease-line jetting for F&B at RM500 – RM1,500 per visit (2026, Klang Valley).
A house drain smell is usually one dry floor trap in a spare bathroom. A business is different. A restaurant kitchen pushes fat, oil and food waste down its drains every service; a cafe runs hot water and detergent all day; a retail unit may have a back toilet and a pantry sink that are hardly used. Each pattern produces its own smell, and customers notice it long before the owner does.
ClickBina's home drain smell guide explains the basic idea that applies everywhere: every trap holds a small water seal that blocks sewer gas, and a smell means a seal has failed or something is rotting on the room side of it. In a business, there are simply more seals, more grease and more pipework shared with neighbours.
| Source | What the smell is like | Typical clue |
|---|---|---|
| Grease trap overdue for emptying | Sour, rancid, worst near the wash-up | Smell builds through the week and drops after a pump-out |
| Dry floor trap under equipment or in a store | Flat sewer smell | Worst on Monday morning or after a closed day |
| Grease-coated drain line | Sour and food-like, worse with hot water | Slow drains at the sinks or floor channels |
| Missing or blocked vent | Sewer smell that comes and goes | Traps gurgle when another sink or the dishwasher drains |
| Building sewer line or inspection chamber | Strong sewer smell at the back lane or in several units | Neighbouring tenants notice it too |
Most smells sit in the first three rows. The last two are less common but are the ones that cost money when they are misdiagnosed as a cleaning problem.
A grease trap slows the wastewater down so fat floats and solids settle, and only the cleaner water in the middle passes to the sewer. ClickBina's grease trap guide notes that a trap left too long turns septic and pushes foul odour back up into the kitchen and dining area. An undersized trap does the same thing faster, because it fills before the shift ends.
The tell is timing. If the smell builds over the days after a clean and disappears after the next pump-out, the trap is being emptied too rarely for the kitchen's load. The fix is a shorter service cycle, not air freshener. If the trap lid is broken or not sealed, the smell escapes even when the trap is not full.
Commercial kitchens and retail back rooms have floor traps in places that rarely see water: under a freezer, behind a fryer, in a dry store, in a staff toilet that is barely used. The water seal evaporates and sewer gas walks straight in. This is the commonest cause in retail units and the cheapest to fix.
Pour water into every floor trap, including the hidden ones, and re-test the next day. If the smell goes, add the traps to the closing checklist. A trap that dries out again within a day is losing its seal another way, which points to venting or a damaged trap rather than evaporation.
Even with a working grease trap, the pipes between the sinks and the trap collect a lining of fat, starch and detergent. Between services it ferments, and hot water softens it and releases the smell. Floor channels with gratings collect food scraps in the corners that rot overnight.
Scrubbing the sink does nothing; the deposit is inside the pipe. A snake opens a hole through a blockage but leaves the coating on the pipe wall. ClickBina's hydro-jetting guide explains why grease lines need a full-bore clean, and why the same blocked drain can be a cheap problem that returns or a proper clearance that holds.
Drain pipes need air. When a large volume of water rushes down, such as a dishwasher discharge or a mop sink being emptied, it can pull the water seal out of a nearby trap if the system cannot draw air from a vent. The trap gurgles, then the smell arrives.
The pattern to report to a plumber is a smell that appears only when another fixture drains. It is easy to misread as a blockage. Fit-outs that added sinks or moved equipment without thinking about the vent are the usual culprits.
Shophouse rows and commercial blocks share sewer lines, inspection chambers and back-lane drains. If several tenants smell the same thing, or the smell is strongest at an inspection chamber outside, the problem may be in shared pipework rather than inside your unit. In a strata building, report it to the management first; ClickBina's sewer stack guide explains how shared stacks are handled.
Grease from one kitchen that skips its trap can coat the shared line and cause smells and back-ups for the whole row. That is one reason councils and Indah Water Konsortium care about grease traps.
The grease trap guide sets out the compliance side: local councils across the Klang Valley, including DBKL, MBPJ, MBSA and MBSJ, require food outlets to install and maintain an adequate grease interceptor, and they inspect for it. Indah Water Konsortium operates the public sewerage system and governs what may be discharged into it. Because the exact wording varies between councils and can change, confirm the current requirement with your council and IWK for your premises.
A smell complaint from a neighbour or a customer is often what triggers an inspection, so fixing the cause properly protects the business as well as the dining room.
These are ClickBina's published market estimates (2026, Klang Valley), not fixed quotes:
| Job | Indicative price | Notes |
|---|---|---|
| Under-sink grease trap clean (per service) | RM150 – RM400 | Frequency depends on kitchen load |
| In-ground interceptor pump-out | RM400 – RM1,200+ | Tanker service; volume and access drive it |
| Under-sink / stainless-steel grease trap supply & install | RM500 – RM2,000 | Size and grade dependent |
| Grease-line jetting (F&B) | RM500 – RM1,500 | Per visit |
| CCTV drain camera inspection | RM200 – RM600 | Often bundled with, or credited against, the clearance |
| Clear a sink, floor trap or floor drain blockage | RM120 – RM350 | Standard localised blockage |
WhatsApp us your job details for a quote — we reply within the hour. A renovation site visit is free, and a repair inspection is RM180, deducted from the bill if you go ahead. We serve KL, Selangor & Putrajaya.
💬 WhatsApp for a quoteRefilling dry traps and adding them to the closing checklist costs nothing, and it solves a large share of retail drain smells. Work done outside trading hours is usually arranged around the business.
ClickBina is an experienced KL & Selangor contractor handling commercial premises and trade coordination. WhatsApp us your job details for a quote and tell us what you have already checked. We reply within the hour, the price we agree is a flat price with no hidden charges, and a renovation site visit is free, and a repair inspection is RM180, deducted from the bill if you go ahead.
How we estimated prices: every RM figure on this page is quoted unchanged from the ClickBina guides named above, where they are published as 2026 Klang Valley market estimates.
WhatsApp us your job details for a quote — we reply within the hour. A renovation site visit is free, and a repair inspection is RM180, deducted from the bill if you go ahead. We serve KL, Selangor & Putrajaya.
💬 WhatsApp for a quoteTell us what you need — we reply within the hour.