UV disinfection in swimming pools: where it fits & who’s using it

So where does UV based disinfection fit in? In commercial and public aquatic facilities, UV is widely used as a treatment installed in the recirculation line, after filtration and before the water returns to the pool.

That positioning is important. It means, if needed, UV can operate as the main disinfection system but it also doesn't have to be a replacement for chlorine in conventional pools. It can also be a complementary barrier that strengthens the overall disinfection strategy.

Who is using UV in the swimming pool industry?

UV systems are now commonly used in higher risk, high bather load and indoor environments. The main operator groups include:

1. Public and community operators

• Local authority leisure centres
• Trust operated community pools
• School and university aquatic facilities
• Competition and training venues

 These sites often manage high bather turnover and are under pressure to meet strict water quality expectations while keeping facilities open year round.

2. Commercial leisure operators

• Private health clubs and gym chains
• Hotels and resort groups
• Waterparks and family entertainment centres

Customer experience is central here. Air quality, clarity, and swimmer comfort directly influence reputation and repeat business.

3. Healthcare and specialist aquatic sites

• Hydrotherapy pools
• Rehabilitation centres
• Specialist treatment pools

In these settings, water quality control is closely scrutinised and risk management is a key driver.

4. Marine and travel operators

• Cruise liners
• Passenger vessels
• Remote or offshore accommodation sites

Here, continuity and outbreak prevention are critical, particularly where facilities operate in semi or fully closed water systems.

Is use of UV growing?

Across the commercial and public pool sector, UV is broadly considered established rather than emerging. It has become increasingly common in:

• New build commercial and municipal pools
• Refurbishments where operators want improved chloramine control
• High bather load installations
• Facilities where there is heightened concern about chlorine tolerant pathogens

The drivers behind continued uptake include:

• Stronger risk awareness around chlorine resistant organisms such as Cryptosporidium
• Pressure to reduce combined chlorine and improve indoor air quality
• The desire to reduce disruptive superchlorination events
• Greater expectation from consultants and designers that secondary treatment is included in higher specification projects

In short, UV is now widely accepted as part of a modern multi barrier approach in many commercial environments.

What does UV actually improve for pool operators?

1. Inactivation of chlorine tolerant microorganisms

Certain pathogens, most notably Cryptosporidium, are highly tolerant to normal free chlorine levels used in pools.

UV systems are designed and validated to deliver a specific dose to circulating water, achieving a defined log reduction of these organisms. This adds a protective layer that chlorine alone cannot reliably provide at typical operating concentrations.

For operators, that means reduced outbreak risk and a stronger defence in the event of accidental faecal contamination incidents.

2. Reduction of chloramines

Chloramines form when chlorine reacts with nitrogen containing contaminants introduced by bathers. They are responsible for:

• The typical “pool smell”
• Eye and skin irritation
• Air quality complaints in indoor pools
• Corrosion issues in extreme cases

Medium pressure UV systems, in particular, are widely used for chloramine reduction because of their broader spectral output. By breaking down combined chlorine compounds in the recirculating water, UV helps operators maintain lower chloramine levels more consistently.

The practical impact for operators:

• Improved swimmer comfort
• Better staff working conditions
• Less reliance on corrective shock dosing
• More stable overall water chemistry management

3. Support for lower overall chemical stress

UV does not eliminate the need for chlorine. However, in many installations it supports a more stable chemical regime by:

• Reducing the build up of chloramines
• Helping maintain clarity
• Supporting more predictable control of combined chlorine

This can translate into fewer emergency interventions and a smoother operating pattern across busy periods.

When should operators review UV lamps and spares

A UV system is only as effective as the dose it delivers. And dose depends heavily on lamp output, sleeve condition, and electrical performance.

One of the most common mistakes in the field is assuming that if the lamp is lit, it is working as designed.

A practical approach for pool operators

1. Replace lamps on a planned schedule

Typical industry guidance indicates:

• Medium pressure lamps often have rated lives in the region of 4,000 to 9,000 hours
• Low pressure lamps commonly range from 8,000 to 16,000 hours

Lamp output declines over time. Even before complete failure, UV intensity may drop below the design requirement. Annual replacement is common in many commercial facilities, although actual change intervals should reflect operating hours and system design.

2. Align stock checks with operational risk

• Operators should review lamp and critical spare stock:
• Before peak seasons such as summer holidays
• Ahead of major competitions or high demand programming
• Prior to planned shutdowns where maintenance can be scheduled
• When UV intensity readings trend downwards

At minimum, many facilities hold:

• A set of replacement lamps
• Quartz sleeves, O-rings and seals
• Critical electrical components such as ballasts

For multi site operators, a centralised spares strategy can significantly reduce downtime risk.

3. Monitor the warning signs

Review your UV system if you notice:

• Rising combined chlorine despite stable chemistry control
• Increased complaints about smell or irritation
• Declining UV intensity readings
• Repeated alarms or electrical faults

These are operational signals that performance may be drifting away from design intent.

Where Alpha-Purify can help

For swimming pool operators and OEMs, UV performance is not just about system design. It is about reliable component supply and predictable lamp performance.

Alpha-Purify manufactures and supplies both medium pressure and low pressure UV disinfection lamps, supporting commercial aquatic installations worldwide. We understand that pool operators need:

• Consistent lamp quality
• Reliable lead times
• Technical clarity around specifications
• Access to associated UV components such as quartz sleeves, O-rings, ballasts, UV sensors and control panels

Whether you are an OEM designing new pool systems or an operator managing replacement cycles across multiple facilities, our focus is simple: Help you maintain design dose, reduce disruption, and keep facilities open with confidence.

If your UV lamps are approaching end of life, or if you are reviewing your secondary treatment strategy, this is the right time to talk. Contact Us

Blog References:

 Model Aquatic Health Code (2023 edition), secondary treatment and UV validation requirements. United States Centers for Disease Control and Prevention.

Healthy Swimming Toolkit, chloramine control and pool operation guidance. United States Centers for Disease Control and Prevention.

Ultraviolet disinfection – specification, maintenance and validation (Technical Note 31). Pool Water Treatment Advisory Group.

UV disinfection best practice materials from major water technology manufacturers including Xylem and Evoqua, discussing chloramine reduction and secondary treatment design in pool applications.