Tsui Lam Estate Drain Services

The minutes of the Sai Kung District Council's second meeting of 2018 (6 March 2018) record a councillor reporting that the Tsui Lam Estate bus terminus “sees sewage seepage and odour problems every year around the middle or second half of the year”, while another said the underground foul drains in the terminus are managed by the Housing Department, with sold private premises — the mall and the market — above them, and that backflow had recurred there for years; the Drainage Services Department replied that it would study improvements together with the Housing Department. The council returned to it by motion on 3 November 2020: a councillor quoted the DSD's written reply (SKDC(M) Paper No. 318/20), in which the department said it believed the seepage and smell originated from silted drains within the estate; the Housing Department's representative told the meeting that “the drainage system in the bus terminus is connected to that of the mall, and drainage from the mall may silt up the terminus system and cause backflow”, adding that the mall side had sent drain tankers to clear blockages in the past. After the meeting, on 11 November, the Housing Department, the councillor, the mall's management and the management company engaged by the owners' corporation inspected the area together and found no blockage or smell at the time. If you smell drains or see wastewater at the terminus, the mall entrances or the footpaths nearby, the practical step is to note the date and time, take photos and pass them to the management office or the relevant department; a drainage problem inside your own flat is handled separately.

Tsui Lam sits on a hill. At the Sai Kung District Council meeting of 5 September 2017 a councillor referred to the estate's “dozen or so slopes”, said some of them are government-maintained and badly affected by illegal cultivation, and worried that in the wet season or after a landslip this “could affect the slopes the estate maintains and cause the channels to silt up”. Inferring from the terrain, heavy rain washes leaves and silt off the slopes into the U-channels, gullies and manholes; once they choke, water runs across podiums, footpaths and ramps to the lowest point, so low-floor corridors and back lanes are hit first. In practice, the channels, gullies and manholes inside the estate are cleared by the owners' corporation and the management company it engages, and the period around a rainstorm is the time to check them. The stretch of Po Lam Road outside the estate — the section between Mau Wu Tsai and Ma Yau Tong on the DSD's Locations Prone to Blockage list — is different: it is a public road drain, so a street inlet buried under leaves can be reported to the DSD directly.

At the Housing and Environmental Hygiene Committee meeting of the Sai Kung District Council on 11 January 2018, a member reported “rats in the drain pipes at On Lam House, Tsui Lam Estate” and asked the Food and Environmental Hygiene Department to raise it with the estate's owners' corporation; the department replied that its staff had inspected Tsui Lam with estate management staff in December 2017 and on 2 January 2018 and found fewer traces of rats. In general, rats get in along damaged pipes, disused outlets that were never sealed, and traps that have dried out or been removed, so baiting alone rarely settles it. If you hear noises in the wall or at a drain, or see stains or smell something around a floor-drain outlet, first check whether the trap still holds water, whether disused outlets are properly sealed and whether exposed pipe joints are cracked, then report it through the management office so the estate can follow up the common parts.

By design, a Trident 2 block puts three wings around a central core, 35 storeys high with 24 flats per floor, and the toilet, basin and bathroom floor drain of flats in the same vertical line discharge into one stack all the way down; the New Slab blocks are only 22 storeys, but their corridor layout puts many flats on each floor, joining a shared horizontal run before the stack. In both designs the low-floor flats take the flow from everything above. If the base of the stack, the horizontal run or a manhole outside is narrowed by grease, tissue and debris, then during the morning and evening peaks or in heavy rain the water level in a low-floor toilet rises first and the floor drain bubbles or backs up. Telling them apart is straightforward: one slow fitment on its own usually means the flat's own branch pipe or trap, while a toilet and floor drain misbehaving together, in time with water use upstairs, means the shared stack belongs in the check and the management office should be told at once.

At the Sai Kung District Council meeting of 1 November 2022, a councillor reported that “part of Tsui Lam Estate consists of sold flats, and seepage cases involving two owners arise from time to time”, adding that affected owners may have little recourse beyond civil proceedings. Seepage and blockage are different problems: a blockage usually shows itself at once as slow draining, backflow or odour, while seepage may come from a waterproofing layer, a pipe joint or an outlet in the flat above, and has to be eliminated item by item. Start with what you can do yourself: stop using the suspect fitment for a day or two and watch whether the damp patch changes, and photograph the marks, their extent and the date. If you suspect a bathroom or kitchen outlet upstairs, have the traps, branch pipes and floor-drain connections in your own flat checked first, then ask the management office to help contact the owner above. Altering a trap, an anti-syphonage pipe or a drain position is minor works under the Buildings Department and must be done by a registered minor works contractor.