Ocean Pride Drain Services

HK01 reported on 26 May 2019 that MTR, replying to enquiries, said developer staff inspecting the affected Block 7 flat found a section of the common drain pipe serving it blocked by items including towels, plastic bags and sanitary products, and that the pipe was repaired immediately. That is one recorded, individual event and says nothing about other flats in the estate. The practical lesson for anyone in a newer building is real enough: during a fit-out or defect rectification, workers often plug drain outlets with cloth, plastic bags or tape to keep grit out, and every plug has to be confirmed removed before completion, with water run through each outlet as a test. The Buildings Department's guidance also notes that a serious blockage by material such as cement may mean exposing and replacing the affected length of pipe rather than simply rodding it.

Building inspector Lai Tat-ming told HK01 that backflow in a new building and on a high floor is very rare, explaining that backflow depends on pipe design and the build-up of rubbish, that narrow or winding pipes let debris collect, and that stacks bend as they approach the lower floors, which is why backflow usually happens in older buildings and on low floors. The general principle is this: sewage comes back out at the lowest fitment above the blockage, so the floor that suffers is set by where the blockage sits, not by how high the flat is. The published reports of the 2019 case do not say which section of pipe was blocked; they record only Lai's estimate that flats above and below might be in the same position. He also listed the most common warning signs — an outlet draining more slowly, or a toilet flushing away slowly. If the bowl refills sluggishly, or the bathtub and floor drain bubble at the same time, have it looked at rather than waiting, so the branch pipe and the stack can be told apart.

HK01 described the high-floor flats in Block 7 as having bathrooms with no window, like those in many new developments — a 「黑廁」. By design, such a bathroom depends entirely on its extract fan: with the door shut and the fan on, the room sits at slightly lower pressure, and if the floor drain or shower trap has an inadequate water seal, sewer air is drawn back into the room. The Buildings Department advises pouring about half a litre of water into each floor drain weekly. Because Ocean Pride was completed in 2019, well before APP-164's 31 August 2021 cut-off, the floor drains installed here are, as an inference from the building's age, conventional traps with no self-refilling arrangement, so they dry out most readily during long trips, between tenancies, or in a guest bathroom that is rarely used. If the smell survives the water, check whether the trap is damaged or has been replaced with a shallower one, and whether the branch pipe is leaking.

In the same report, Lai Tat-ming noted that many interiors are now designed without a marble threshold or a drain outlet at the kitchen or bathroom doorway, which makes the damage worse when wastewater escapes. HK01's description of the Block 7 high-floor flats records open-plan kitchens, and many owners also choose a level, sill-free bathroom floor when they renovate. It looks better, but if a toilet or floor drain backs up the water reaches the corridor and bedrooms quickly. This does not change the unblocking work itself; it changes the clean-up. After a backflow the job is not finished when the pipe runs clear — the floor needs thorough cleaning and disinfection, and timber flooring, cabinet plinths and skirting all need checking.

Not one residential floor at Ocean Pride sits near ground level — the lowest is the 6/F platform — and the balconies look straight out over Rambler Channel. The usual confusion here, then, is not a smelly manhole downstairs but an outdoor smell off the waterfront drifting in through an open balcony door or window and being taken for a drain smell indoors. The waterfront odour itself is a public drainage matter for the area: the Drainage Services Department's project 4450DS, to build dry-weather flow interceptors on Tsuen Wan's stormwater drains, states its main environmental benefit as improving the water pollution and odour of Victoria Harbour, and is currently in planning and design. Dry-weather flow interceptors exist to catch wastewater that has found its way into stormwater drains, which is exactly what misconnected pipes cause. To tell them apart, shut the balcony door and the windows and come back half a day later: if the smell has gone it came from outside, and if it is still there and strongest in the bathroom or under the sink it is a water seal or a branch pipe of your own. For what it is worth, the department's list of coastal low-lying or windy residential areas names only Sham Tseng San Tsuen in Tsuen Wan District, not the Tsuen Wan West waterfront.