Water Tank Cleaning & Disinfection
Clean Water Starts With Clean Storage
Cold water storage tanks can collect sediment, rust, scale, debris and biofilm over time. These provide nutrients and shelter in which Legionella and other bacteria can multiply. A tank in poor condition can contaminate the water supplied to every outlet in your building. Stravica delivers professional tank cleaning and disinfection that restores your stored water to a safe, hygienic condition, in line with HSE guidance and British Standards.
When Tanks Need Cleaning And Disinfection
HSE guidance HSG274 requires cold water storage tanks to be inspected at least once a year. Cleaning and disinfection are needed when:
- An inspection finds sediment, debris, vermin, biofilm or contamination.
- Sampling shows significant bacterial colonisation.
- A new system is installed, or an existing one is modified or opened for repair.
- A building or system has stood unused for a long period.
- The authorities ask for it during an outbreak.
A Safe, Planned Approach
Tank cleaning is high-risk work. It can involve confined spaces, hazardous chemicals and work at height. Every job is carried out under a written method statement and a permit to work, by trained and competent operatives. Entry into tanks is avoided wherever possible. Where it is unavoidable, it follows the Confined Spaces Regulations, with gas monitoring, ventilation, a trained top-person and a rescue plan in place. Your site, your people and our operatives are protected throughout.
Thorough Cleaning
Tanks are isolated and drained in a planned sequence to keep disruption to a minimum. Sediment, sludge and debris are removed and safely contained, and internal surfaces are cleaned. The tank is then inspected for defects such as damaged linings, ill-fitting lids, missing insect screens, overflow problems or poor insulation. Any defect that could let contamination back in is reported with clear recommendations for repair or replacement.
Verified Disinfection
Disinfection is carried out in line with HSG274, BS 8558 and BS EN 806, typically using chlorine at 50 mg/l for at least one hour, or as set out in the approved method statement. Chlorine levels are tested at the start and end of the contact period to confirm that disinfection has been effective. Outlets are tagged "Do Not Use" and signed throughout, so no one is exposed to treated water.
Responsible Discharge
Water at disinfection strength is highly toxic to fish and aquatic life, so it must never reach a surface water drain or watercourse. Before any discharge, the water is neutralised and tested at the discharge point to confirm the chlorine has been removed. It is then released at a controlled rate into the foul sewer, with water company consent where required. Surface water drains are covered before chemicals arrive on site, and spill kits are always at hand.
Minimal Disruption To Occupants
We know tank work affects the people in your building. Residents and occupants receive advance notice of any interruption to their water supply. Alternative supplies are arranged for vulnerable residents and critical services, such as care facilities and kitchens. Work is scheduled at the times that cause least disruption, and the supply is restored only after the water has been flushed and verified.
Calorifiers And System Disinfection
Our cleaning and disinfection services go beyond cold water tanks. They include:
- Draining and cleaning calorifiers and hot water storage vessels.
- Disinfecting whole distribution systems after contamination or adverse sampling results.
- Chlorinating new and modified installations before they are brought into use.
- Thermal disinfection where it is the most appropriate method.
Evidence You Can Rely On
Every job is fully documented. You receive before-and-after photographs, chlorine verification results, the discharge record and a completion certificate. Where specified, microbiological verification samples are taken before the system returns to normal use. Records are added to your digital logbook, giving you complete, auditable evidence for inspections and insurers.
Accountable Delivery You Can Trust
Tank cleaning and disinfection is delivered by trained operatives from Legionella Control Association member organisations, holding the confined space and water hygiene qualifications the work requires. All work is managed and quality-assured by Stravica. You get one point of contact, safe and compliant work, and complete records.