How often should a cooling tower be cleaned?

What does the EMSD Code of Practice say about cleaning frequency?

The Code requires cleaning, desludging and disinfection at least every 6 months. It also sets rules people routinely miss: a standby tower should still be run at least one hour per week, and a system out of use for more than a week must either be kept full of treated water and circulated weekly, or fully drained and dried. Full recommissioning, including cleaning and disinfection, is required before it goes back into service. See the EMSD Code of Practice explained.

What sets the frequency

The right frequency depends on how the tower is used, its condition, the local environment, and the results of water tests. A tower in heavy year-round use may need more frequent cleaning than one used seasonally.

When is an extra clean needed?

Clean sooner if a Legionella or water test comes back high, if the tower has been idle and is restarting after a shutdown or typhoon, or before the cooling season. A high result should always be followed by cleaning and disinfection, then a re-test — if that is where you are now, see emergency response.

What a clean, desludge and disinfection visit involves

A routine clean is more than a hose-down. The basin is drained and desludged — it is the single biggest reservoir of nutrient and bacteria — the fill, drift eliminators and wetted surfaces are cleaned, the whole system is disinfected rather than just the visible parts, the drift eliminators are checked because they are the aerosol control, and the tower is refilled and returned to service with a dated report for your records. Where biofilm has taken hold, a biodispersant is circulated first so the disinfectant can reach the bacteria it shelters. The full sequence is on our cooling tower cleaning page, and biofilm in cooling water systems explains the biodispersant step.

The other clocks the Code runs alongside the 6-month clean

• Legionella and heterotrophic colony count are sampled at least quarterly while the tower is under control.
• A heterotrophic colony count of 100,000 cfu/mL or more requires immediate cleaning and disinfection, whatever the calendar says.
• A standby tower should still be run at least one hour per week, with treatment and monitoring continuing on any unit that holds water.
• Operation and maintenance records must be kept for at least 2 years and be available for inspection.

All four are set out in the EMSD Code of Practice, explained; the printable compliance checklist tracks them month by month.

How Gotech handles it

We assess your tower, set a cleaning and disinfection schedule that keeps you compliant, and carry out extra cleans quickly when a result calls for one. See cooling tower cleaning, and print the cooling tower compliance checklist to track each clean.