Your Trusted Partner for Backflow Prevention
If you’re here, there’s a good chance you’re responsible for keeping your building’s water supply protected from contamination - and you know how important backflow prevention is for meeting legal and safety standards.
You’re in the right place. At Titan Water, we provide professional backflow prevention services, including RPZ valve testing, Cat-5 tank installations, double check valve installations, and consultancy on fluid risk categories. Our engineers help you meet the requirements of the Water Supply (Water Fittings) Regulations and ensure your system has the right level of protection for its fluid category.
We take a practical, compliance-focused approach. That means accurate risk classification, correct device selection, and proper installation and testing of all backflow prevention equipment. Whether you need an annual RPZ test, a Cat-5 solution for a commercial process, or guidance on choosing the right backflow arrangement, Titan Water will help you stay safe, compliant, and fully protected.
Nationwide Service
Reliable Expertise Wherever You Are
Our experienced management team operate from the Titan head office near Liverpool, but while our roots are in the North West, our reach extends across the UK. Our engineers carry out RPZ testing, Cat-5 installations, and backflow prevention work nationwide. Whether it’s a factory in Sheffield, a dental practice in Brighton, or a commercial process plant in Glasgow, we’ve been there – and we understand the regulations that apply to each fluid risk category.
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If you’re unsure whether your system is adequately protected or you need help selecting the right backflow prevention device, the team at Titan are always happy to offer clear, practical advice.
What Is Backflow Prevention?
Backflow prevention is the process of stopping contaminated water from flowing back into a clean water supply. In the UK, it is a legal requirement under the Water Supply (Water Fittings) Regulations and must be designed according to the fluid risk category of the system.
Backflow can occur through back pressure or back siphonage, allowing contaminated water from processes, tanks, equipment, or appliances to re-enter the potable supply. To prevent this, the correct device must be installed - ranging from double check valves to Cat-5 arrangements and RPZ valves for higher-risk uses.
Key objectives:
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Protect drinking water from contamination
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Meet Water Regulations and fluid category requirements
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Ensure safe use of appliances, tanks, and process equipment
What Is an RPZ Valve and Why Is RPZ Testing Required?
An RPZ (Reduced Pressure Zone) valve is a specialist backflow prevention device used for Fluid Category 4 risks, where contamination risk is significant but not toxic. RPZ valves offer advanced protection by maintaining a reduced pressure zone and safely discharging water if backflow is detected.
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RPZ testing is required annually by a certified tester to ensure the valve is functioning correctly, maintains the correct pressure differential, and complies with UK water regulations. If a valve fails, it must be repaired or replaced immediately.
RPZs are typically installed on:
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Commercial process lines
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Food production systems
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Wash-down hoses and equipment
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Labs and industrial equipment
Proper RPZ testing provides assurance that your system is operating safely and legally.
What Are Fluid Risk Categories and How Many Are There?
Fluid risk categories are part of the UK Water Supply (Water Fittings) Regulations. They classify water systems based on the level of contamination risk they pose, and they determine what type of backflow protection is legally required.
There are five fluid categories, each representing a higher level of contamination risk:
Fluid Category 1 – Wholesome Water
Water direct from the mains, safe for drinking.
Examples: Drinking taps, kitchen sinks.
Fluid Category 2 – Aesthetic Changes Only
Water slightly altered in appearance, taste or temperature, but still safe.
Examples: Heated drinking water, softened water.
Fluid Category 3 – Moderate Health Risk
Water containing low-grade contaminants, additives or substances of low toxicity.
Examples: Commercial hose union taps, heating systems, laundry equipment.
Fluid Category 4 – Significant Health Risk
Water contaminated with harmful but not highly toxic substances.
Examples: Process chemicals, commercial dishwashers with detergents, industrial equipment.
Fluid Category 5 – Serious Health Hazard
Water that contains or could contain faecal matter, pathogens, pesticides, or highly toxic substances.
Examples: Toilets, urinals, washdown systems, animal facilities, some lab and medical equipment.
Knowing the correct fluid category is essential - it dictates the exact backflow prevention device required to comply with the Water Regulations.
Which Backflow Prevention Devices Are Required for Each Fluid Risk Category?
Each fluid category has a specific level of backflow protection assigned to it. Using the wrong protection can lead to contamination risks, enforcement notices, and non-compliance with the Water Fittings Regulations.
Here’s how the categories line up with their required devices:​​​​​​​​​​​​​​​​​​​​​​​​​​​
Fluid Category
Category 1
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Category 2​
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Category 3
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Category 4
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Category 5
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Description of Risk
Wholesome water straight from the mains.
Slight aesthetic changes but still safe for consumption.
Medium-grade contaminants of low toxicity.
Significant health risk from harmful but not highly toxic substances.​
Serious health hazard including faecal, bacterial or toxic contamination.
Common Examples
Drinking taps, kitchen sinks, potable outlets.
Warm/softened water, chilled drinking dispensers.
Commercial hose taps, heating systems, laundry equipment.
Process equipment with chemicals, commercial dishwashers, industrial plant.
Toilets, urinals, washdown hoses, animal facilities, some medical/lab equipment.
Required Backflow Prevention Device
None (standard plumbing only)
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Single Check Valve (Type EA)
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Double Check Valve (Type EC/ED)​
RPZ Valve (Type BA) — requires annual testing​
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Cat-5 Protection: Type AB air gap or Cat-5 break tank
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Explore Our Full Range of Services
Case Studies
Want to learn more about the kind of work we do? Well you're in luck, as our 'Case Studies' pages are the perfect way to explore some of the 700+ projects we deliver every year, offering a glimpse into the challenges we've faced and the innovative strategies our team have employed to deliver excellence for our customers.
Our Clients
Appointed on our reputation, retained on our results!
With over 75 years of water management experience, Team Titan have become trusted partners to some of the UK's leading corporate brands.
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