Sceneway Garden Drain Services

Beneath the flats at Sceneway Garden are a mall, a transport interchange and Lam Tin station, so, as an inference from that layout, each block's stacks are likely to turn into horizontal collector pipes at podium level before reaching the public sewers outside. Those runs have gentle falls and many bends, so kitchen grease, wet wipes and renovation debris settle in them; once a run narrows, heavy discharge from upper floors shows up first at the toilets and floor drains of the lowest floors above the podium, as rising water, bubbling or backflow. If several flats in the same block are affected, or it always happens at peak water-use times upstairs, ask the management office to check the shared pipes first; if only one outlet is slow, the flat's branch pipe or trap is more likely, and that can be handled on a call-out.

The Buildings Department explains that when enough sewage is discharged from an upper flat, siphonage creates negative pressure in the branch pipes of the flats below, strong enough to pull the water seal out of their traps; the anti-syphonage pipe balances that pressure and must extend at least 1 m above the roof. Each Sceneway Garden block is 28 to 34 storeys, so one stack serves many floors. If your toilet's water level drops by itself, or the basin or floor drain gurgles when someone else flushes and a sewer smell follows, check whether an anti-syphonage pipe or valve has been removed during renovation or is blocked, rather than just pouring in bleach to cover the smell.

Wikipedia records that the 910 to 913 sq ft three-bedroom flats with an en-suite occupy the outer positions in Blocks 9 to 17, while the 674 to 680 sq ft two-bedroom flats are only in units A to D of Blocks 1 to 8; no public source gives the number of bathrooms per flat. Inferring from the 'three-bedroom with en-suite' layout, those flats will have a second set of fixtures and a floor drain in the en-suite on top of the main bathroom — one more water seal to look after. The Buildings Department explains that toilets, basins and bathtubs are used daily, so the seals in their traps rarely dry out, but a floor drain left unused for a long time, or never topped up with clean water, loses the seal in its trap to evaporation and with it the barrier against sewer air. An en-suite that is seldom used, a room left empty before letting, or a long trip away is the usual way that happens, and the smell is often most obvious as you open the door or tidy the room. The department advises pouring about half a litre of water into every floor drain at least once a week; if two or three weeks of that has not eased the smell, check whether the trap is cracked, whether renovation replaced it with a shallow-seal type, or whether a branch-pipe joint is leaking.

According to an HK01 report in February 2021, a first-floor flat of about 700 sq ft in the estate had been divided into five suites for rent, each of about 112 to 150 sq ft and each with its own toilet; the owner's post stressed that the plans were 'legally submitted', while online commenters worried about what would happen 'if one of them blocks'. Five toilets plus cooking areas mean far more outlets than a normal layout, and all of them have to join the original branch pipes and stack. The Buildings Department says drainage added when kitchen or bathroom layouts are changed must be installed by a registered contractor under the Minor Works Control System, with an effective water seal on every fitment, and that the same rules apply to subdivided flats. If you notice new odour or seepage after a flat above or below has been converted, take photos and tell the management office.

The Buildings Department's Mandatory Building Inspection Scheme covers private buildings aged 30 years or more. Once served a statutory notice, owners must appoint a registered inspector to inspect the common parts, including drainage on external walls, drainage in common pipe ducts, and the above- and below-ground common drainage system. The Sceneway Garden blocks are now about 34 to 35 years old; as a general inference from age, problems such as rusty external pipes, loose pipe brackets and leaks in podium-level pipes will gradually appear, and these are common parts coordinated by the management office and the owners' organisation. Branch pipes and traps inside a flat are generally not common parts, so owners need to watch those and arrange checks themselves.