- Backflow is the reversal of water flow in a plumbing system, which can contaminate potable water supplies with pollutants, chemicals, or biological hazards.
- Backflow testing verifies that backflow prevention devices (BPDs) are functioning correctly and protecting the water supply.
- All commercial buildings connected to public water mains in Kenya are required to have backflow prevention devices installed and tested regularly.
- Testing must be carried out by certified plumbing professionals using calibrated pressure gauges and testing equipment.
- Failed devices must be repaired or replaced immediately to restore protection and maintain compliance.
- Bestcare Facilities Management provides professional backflow testing and prevention device installation services across Nairobi and Kenya.
Clean, safe water is fundamental to public health. Yet in any plumbing system, there exists the risk that water can flow in the reverse direction — travelling back from a building’s internal plumbing into the public water main and potentially contaminating it with whatever the internal pipework has been in contact with. This phenomenon, known as backflow, can occur due to back-pressure (where the building’s internal pressure exceeds the mains supply pressure) or back-siphonage (where a negative pressure or vacuum develops in the supply line).
The consequences of backflow contamination can be severe. Industrial chemicals, pesticides, fertilisers, bacteria from irrigation systems, and medical fluids from hospital equipment can all enter the potable water supply through backflow events. This is why backflow prevention devices — and regular testing to verify their correct operation — are a critical component of any commercial building’s plumbing compliance programme. In Kenya, where water infrastructure in many areas already faces pressure challenges, maintaining effective backflow prevention is both a regulatory requirement and a public health imperative.
Understanding Backflow Prevention Devices
Air Gaps are the simplest and most reliable form of backflow prevention — a physical gap between the water supply outlet and the maximum possible water level in a tank or vessel, preventing any possibility of back-siphonage.
Double Check Valves (DCVs) are mechanical devices containing two independent check valves in series, providing protection against back-pressure and back-siphonage for moderate-risk applications such as irrigation systems and fire suppression systems.
Reduced Pressure Zone (RPZ) Assemblies provide the highest level of mechanical backflow protection, incorporating two check valves and a pressure-differential relief valve that opens to discharge water if either check valve fails. RPZ assemblies are required for high-risk connections such as chemical dosing systems, hospital equipment, and industrial processes.
Hose Union Backflow Preventers are simple, inexpensive devices fitted to outdoor tap and hose connection points to prevent back-siphonage from garden hoses and irrigation connections.
Backflow Testing involves connecting calibrated pressure gauges to the test ports of mechanical backflow prevention devices and verifying that each check valve holds the required pressure differential and that the relief valve operates at the correct set point. Testing must be performed annually or as specified by the water services provider.
Why Regular Backflow Testing Matters
A backflow prevention device that is not tested regularly may fail silently — appearing functional while no longer providing adequate protection. The only way to confirm that a device is working correctly is through physical testing with calibrated equipment by a qualified technician. In Kenya, WASREB and county water service providers require that all mechanical backflow prevention devices on commercial connections be tested at least annually, with test reports retained for inspection.
Properties found to have non-functional or untested backflow prevention devices may face disconnection from the water supply network, fines, and liability for any contamination event that occurs.
Estimated Cost of Backflow Testing Services in Kenya
| Service | Unit | Estimated Cost (KES) |
|---|---|---|
| Annual backflow test (DCV) | Per device | 5,000 – 15,000 |
| Annual backflow test (RPZ assembly) | Per device | 8,000 – 25,000 |
| DCV supply and installation | Per device | 15,000 – 60,000 |
| RPZ assembly supply and installation | Per device | 40,000 – 150,000 |
| Hose union backflow preventer supply/install | Per unit | 3,000 – 8,000 |
| Failed device repair | Per device | 10,000 – 50,000 |
| Full site backflow risk assessment | Per site | 20,000 – 80,000 |
| Annual testing contract (multiple devices) | Per year | 30,000 – 150,000 |
Note: Costs are indicative and depend on the number and type of devices, site accessibility, and whether repairs or replacements are required. Contact Bestcare Facilities Management for a site-specific quotation.
Contact Information
| Detail | Information |
|---|---|
| Company Name | Bestcare Facilities Management |
| Phone | 0709 004 600 |
| Address | Mpaka Plaza, Westlands, Nairobi |
| info@bestcareservices.co.ke | |
| Website | www.bestcareservices.co.ke |
Contact us today for a free consultation and competitive quotation for your backflow testing and prevention requirements.