Commercial maintenance
Backflow prevention (RPZ) testing
Annual RPZ device testing and certification for Fluid Category 4/5 premises. Required by the Water Supply (Water Fittings) Regulations 1999.
Annual Reduced Pressure Zone (RPZ) device testing and certification for commercial premises classified Fluid Category 4 or 5 under the Water Supply (Water Fittings) Regulations 1999. Same engineers, same compliance pack, same paperwork format as our TMV and Legionella work.
What's tested, what's certified
Every RPZ device on site tested per WRAS guidance: differential pressure, relief valve operation, check-valve seal integrity, and isolation valve function. Per-device test record listing each reading. Single coversheet acceptable to local water undertakers (Thames Water, Affinity Water, Essex & Suffolk Water).
When RPZ testing is needed
Annual statutory test
Every RPZ device on a commercial site must be tested annually by an approved tester and certified to the local water undertaker. Missing the annual test puts the supply at risk of disconnection.
Commissioning new RPZ install
After installation or replacement, the device needs commissioning and a baseline test record. We commission and certify in one visit.
Change of use of premises
Premises changing from low-risk to high-risk Fluid Category use (e.g. opening a food-prep area in a former office) often need new RPZ protection. We survey, install, and certify.
Insurance or licence renewal
Underwriters and council licensing officers increasingly request a current RPZ test certificate. We provide same-day paperwork.
What it costs (indicative)
Per-device fixed-price test including certification and submission to the water undertaker. Multi-device site pricing on a single visit. Materials at trade cost plus 30% markup where remedial work is needed (worn check valves, seal kits, etc.). Full pricing.
Sectors that typically need RPZ protection
- ✔ Restaurants, commercial kitchens, food-prep premises (Fluid Category 5)
- ✔ Dental surgeries and medical centres (Fluid Category 5)
- ✔ Laboratories and research facilities (Fluid Category 4/5)
- ✔ Car washes, vehicle workshops, dosing systems (Fluid Category 4)
- ✔ Hotels and leisure venues with pools, spas or hot tubs (Fluid Category 4)
- ✔ Industrial process water installations
Why bundle with us
Our engineers are already running TMV testing and Legionella risk assessments on commercial sites across London. Adding RPZ testing to the same site visit means one engineer, one access pass, one certificate pack, one invoice. We coordinate test scheduling so all your annual water-compliance paperwork lands in the same week.