Septic tanks & wastewater treatment plants

Septic tanks and wastewater treatment plants in Hong Kong

Updated 4 November 2026

In Hong Kong, bacterial septic treatment products are listed at about HK$120 to HK$285, polypropylene septic tanks from about HK$740 to HK$9,000, and household sewage treatment plants from about HK$23,500 to HK$39,300 (approximate, according to sellers' websites, November 2026). Prices depend on tank volume, the number of residents and the site, so the fastest route to a real figure is a request on BlaBlaPrice.

Local rules you must follow

Under the Water Pollution Control Ordinance (Cap. 358), polluted water may not be discharged into stormwater drains, according to the Environmental Protection Department. The Water Pollution Control (General) Regulations (Cap. 358D) list a layout plan and schematic diagram among the required items. Septic tanks also have statutory requirements in Hong Kong, including a minimum of 18 m from a stream or well.

The Drainage Services Department also gives start-up help for newly set-up private sewage treatment plants, and government guidance notes cover the design of septic tanks and soakaway systems. Ask the seller to show how the system follows them before you buy.

Season, use and timing

Winter runs from December to February and summer from June to August, and November is between the two. Household use depends on the number of residents and whether the home is permanent or seasonal, so say which applies.

How it is bought and installed here

Name your district (Central, Kowloon, Sha Tin, Tsuen Wan or Tuen Mun) and the site address, because soil and water conditions matter for the tank type. Give tank volume in litres and check that the installation fits the site, since the setback from streams and wells is a legal minimum.

What to put in your request

Give the number of residents, whether the home is permanent or seasonal, the soil and water conditions, and the volume you need in litres. Add the make and model if you already have a tank, the installation site, whether you need installation, and your budget.

Describe your home, the number of people living there and your budget in your own words in a chat on BlaBlaPrice, and add a photo of the site if you have one. The AI asks for missing details, searches sellers' websites and price lists in Hong Kong, and shows the prices and businesses it finds. Sellers registered on BlaBlaPrice reply in the chat with their own offer, including terms and installation. For related work, see Plumbing and Building and renovation.