What blocks ac condensate drain unblocks in Sham Shui Po

Algae build-up in flexible drain pipe (humid HK climate)

Dust + lint from AC filter blowing into drain

Pipe slope incorrect causing water pooling

Outdoor pipe end blocked by debris

Sham Shui Po building patterns we see

1960s clay pipe corrosion + roughness traps debris

Restaurant grease leaching into shared mains over 30 years

Tile-on-tile bathroom conversions stacking debris-catching joints

Subdivided unit (劏房) extra fittings creating extra failure points

Method Compressed-air blow-through → vinegar flush → check pipe slope → test 10-min AC run for re-pooling.

Sham Shui Po-specific knowledge. Sham Shui Po has the highest concentration of pre-1995 walk-ups in HK. Clay pipes, narrow drain bores, decades of accumulated grease — drains here block 3-5× more often than newer districts. We've cleared 80+ Sham Shui Po jobs and know the patterns.
Service-specific method. AC dripping water inside / from outdoor unit = clogged condensate drain in 95% of cases. Blockage is dust + algae build-up at the narrow flexible drain pipe. 10-15 min job. Most-undercharged HK service.
Fixed price quoted on phone. No 'we'll see when we get there' surprises. From HKD 250.
7-day re-block guarantee. Same drain re-blocks within 7 days, we return free.
Receipt + tax invoice always. For tenant-landlord reimbursement or building AP.