Commercial maintenance
Cold water storage tank cleaning
L8 / HSG274-compliant tank cleaning, chlorination, and certification for commercial blocks. Pairs with the legionella risk-assessment programme.
Cold Water Storage Tank (CWST) cleaning, chlorination, and certification to HSG274 standards. The natural companion to the legionella risk-assessment work we already run on commercial blocks across London.
What we do, end to end
Visual inspection of the tank interior. Drain, brush-and-vacuum clean of sediment. Hyperchlorination dose to 50ppm, hold for one hour, neutralise and re-flush. Re-fill to working level. Bacteriological sample sent to a UKAS-accredited lab. Pass certificate by email within five working days, with photographic record of the before-and-after state.
When CWST cleaning is required
Annual / biennial L8 schedule
HSG274 Part 2 recommends inspection and (where needed) cleaning every 6-12 months depending on usage. We schedule + remind.
After a contamination event
Dead bird, foreign object, broken tank lid, ingress of debris. Same-day extraction + chlorination service.
High legionella sample count
Where an L8 sample has flagged positive, we clean, re-dose, and re-sample to bring counts back inside acceptable range.
Building handover or acquisition
Baseline clean + certificate establishes a clean starting state for the new owner or managing agent.
What it costs (indicative)
Fixed-price per tank based on capacity (small <500L, mid 500-2000L, large 2000L+). Multi-tank or multi-site contract pricing available. Lab sample fees included. Full pricing.
How it integrates with our wider water-hygiene service
We coordinate tank cleaning with the same engineers running your Legionella risk assessment + TMV testing + RPZ testing. One visit, one engineer, one compliance pack covering every L8 line item. The certificate set is formatted to drop straight into your building's water-hygiene file.
When to call us
- ✔ Your annual CWST inspection is due.
- ✔ A legionella sample has flagged positive and you need a re-clean.
- ✔ Debris or contamination has been observed in or around a tank.
- ✔ You're acquiring a building and want a baseline clean + certificate.