Swimming pool water treatment

Service scope updated 5 September 2026: assessment, visit frequency, reporting and chemical supply arrangements are agreed in the quotation. This overview does not replace the pool’s own licence or operating procedure.

What the programme covers

Pool water has two jobs to get right, and they are tested and managed separately. Disinfection is the chlorine. Balance — pH, total alkalinity and calcium hardness — decides whether that chlorine works and whether the water is quietly attacking the grout, the fittings and the heater. A treatment programme holds both at once, on a schedule, with the paperwork to show it.

• Disinfection — product and dosing arrangements reviewed against the licence and operating requirements, with options including slow-dissolve chlorine tablets, sodium hypochlorite as appropriate to the approved equipment and treatment procedure
• Water balance — pH, total alkalinity, calcium hardness and cyanuric acid results reviewed together, with correction priorities established from the pool’s current conditions
• Daily testing support — DPD No. 1 and phenol red comparator kits and reagent refills for the register the licence requires, with replenishment quantities, availability and delivery timing confirmed by quotation (see pool test kits)
• Scheduled testing — at the frequency agreed for the service scope, providing results to file alongside the operator’s daily register
• Laboratory certificates — bacteriological and clarity results through a HOKLAS-accredited independent laboratory, the evidence FEHD's own guide points to (see laboratory testing)
• Chemical supply — chlorine, pH and alkalinity correction, algaecide, clarifier and test reagents for Hong Kong pools; supply quantities, availability and any proposed delivery schedule are confirmed in writing (see pool chemicals)
• Automatic dosing and monitoring where the pool justifies it — system options and sensor parameters assessed for the pool. Confirm the equipment scope, alarm arrangements and routine verification responsibilities (see real-time monitoring & dosing)
• A dated report after every visit — in plain language, filed next to the register, readable by a committee or an inspector

What happens on site

1. Survey. Pool volume, plant room, filtration turnover, how the pool is dosed today, and what your own licence and letter of requirements say — FEHD can stipulate non-standard conditions for an individual pool. We test the fill water too, because calcium hardness is set mainly by what comes out of the tap.
2. Set the programme. Review the proposed chlorine source against the product label, equipment instructions, recent water results and the pool’s operating requirements. Confirm any product or dosing-setting change with the responsible operator. Routine testing and attendance remain necessary with either tablets or automatic dosing.
3. Scheduled testing. pH, free and combined chlorine, total alkalinity, calcium hardness and cyanuric acid, with a plain statement of what to correct and in what order.
4. Laboratory sampling. Samples taken at the right point, at bather depth and away from an inlet, handled correctly on the way to the laboratory, analysed by a HOKLAS-accredited independent laboratory and returned as a formal dated certificate.
5. Chemical delivery. Plan quantities using actual consumption and appropriate storage arrangements. Confirm the product specification, availability, delivery date and any proposed replenishment frequency in the quotation.
6. Report. A dated written report after every visit: what was tested, what it read, what was done and what the operator should do next.

The numbers a licensed pool has to hold

Under the Swimming Pools Regulation (Cap. 132CA), a pool that the public can use, or that is operated by a club, institution, association or other organisation, must hold a licence from the Director of Food and Environmental Hygiene. The only exemption FEHD publishes is a pool serving not more than 20 residential units with no public access — so almost every estate clubhouse, hotel and club pool is a licensed pool. The licence sets working numbers, and the chlorine and pH duties are continuous: at all times bathers are in the water, not at the morning test.

FEHD accepts a pool water test report from an accredited laboratory as evidence that the plant can hold the standard, and the government told the Legislative Council in 2023 that FEHD inspects licensed pools monthly while they are open. Your own licence and letter of requirements are the final word for your pool; the full set of obligations, including the lifeguard and record-keeping conditions, is set out in swimming pool licence requirements in Hong Kong.

Assess the water results together

Water readings need to be considered together. Chlorine concentration, pH and stabiliser affect disinfection; water balance also matters to the pool finish and equipment. A reading from one test is not a complete diagnosis. The CDC explains the importance of routine chlorine and pH testing.

Agree a treatment response from current results, product instructions and the operator’s procedure. Do not assume that a chlorine product automatically calls for acid or alkalinity additions. See pool water balance for background, and the chlorine purchasing comparison for the information to gather before changing supply.

What Gotech does — and does not — do at a pool

We are a water treatment company. At a pool that means the chemistry, the testing, the chemicals and the laboratory paper trail. It does not mean the deck.

• We do not provide lifeguards. The licence fixes a minimum number of qualified life-saving attendants at the pool edge and the signed duty logs behind them, retained for at least 90 days. That is the pool management company's responsibility, and we do not offer it.
• We do not clean or staff the pool. Vacuuming, skimming, tile and deck cleaning, changing rooms, attendants and opening hours stay with the pool operator.
• We work alongside the pool management company. Their attendants take the daily DPD reading with kits and reagents we supply; their register and our scheduled results sit in the same file; our report tells both of you what to correct and in what order. One contractor for the water, one for the pool, and paperwork that agrees with itself.

One boundary case is worth naming. Where a water storage tank fills the pool, FEHD's licence conditions require its inside thoroughly cleansed every three months while the pool is in use. That is water treatment work, and we do it: see Potable water disinfection.

Who this is for

Estates and clubhouse pools. The decision is made by an owners' committee or managing agent who must justify the spend to residents, so quotations are written so they can be tabled at a meeting and reports are in plain language residents can read. The same committee usually owns fresh water tanks and cooling plant too — see water treatment for estates & pools.

Hotels and clubs. Pool treatment can be discussed alongside cooling towers and hot water services. Confirm the scope, working hours and reporting requirements needed by the hotel or club in the quotation — see water treatment for hotels.

Gotech has treated Hong Kong water systems since 1982. Client names are kept private; reference lists are shared with quotations on request.

Frequently asked questions