CWST Inspection
Watch: Step-by-Step Demo
Purpose
To check cold water storage tanks to make sure they are clean, cold, and sealed properly.
Required Equipment
Inspection checklist, torch, camera, calibrated thermometer, measuring tape
Required PPE
Gloves, hard hat, safety boots, hi-vis vest, dust mask if dusty
Required Tools
Torch, camera, thermometer, inspection mirror, confined space permit if needed
Step-by-Step Method
- Get to the tank room or loft. Make sure you can get there safely (ladder, lighting).
- Look at the outside of the tank - check for leaks, rust, damage, and insulation.
- Take the lid off carefully. Do not drop anything in.
- Check the lid - it must be strong, tight-fitting, and secured.
- Check the inlet - make sure the float valve works and the water level is right.
- Check the overflow and warning pipe - must have fine mesh (0.65mm or smaller).
- Check the vent - must have mesh and point downward.
- Look inside - check for dirt, slime, scale, rust, and debris.
- Measure the water temperature - must be 20 degrees C or below.
- Check inlet and outlet are at opposite ends (to stop water sitting still).
- Check for cross-connections or backflow risks.
- Take photos of the inside and any problems.
- Fill in the checklist.
- If cleaning is needed, start the CWST cleaning procedure.
Pass Criteria
Water temperature 20 degrees C or below. Lid is strong and secured. All openings have mesh (0.65mm or smaller). Inside is clean - no dirt, slime, or rust. Inlet and outlet in the right place. No cross-connections.
Fail Criteria
Water temperature above 20 degrees C. Lid missing, loose, or weak. Mesh missing or damaged. Visible contamination. Wrong inlet/outlet position. Cross-connections present.
Common Problems & Corrections
Temperature above 20 degrees C - Improve ventilation or insulation. Check for heat sources nearby. Slime or dirt - Clean and disinfect the tank. Damaged lid or mesh - Fix or replace right away. Water sitting still (stagnation) - Check outlet position. Think about making the tank smaller. Rust - Check how bad it is. Line or replace the tank if bad.
Warnings
Going inside a tank may need a permit and gas detector. Never go in alone. Turn off electricity if there is equipment inside. Make sure there is enough light and air.
Relevant Legislation
ACOP L8 (4th Edition), HSG274 Part 2, Water Supply (Water Fittings) Regulations 1999