Tank relining helps prevent contamination in water tanks by sealing the inside of the tank with a durable protective coating. This layer stops bacteria, rust and debris from entering the water, keeping it safe and hygienic. In this guide, we’ll explain how tank relining prevents water tank contamination and the key benefits of using a protective tank coating.
Understanding What Tank Relining Is
Tank relining involves applying a protective coating to the inside surfaces of a water tank system. This coating helps maintain the tank’s structural integrity, extending its lifespan while protecting the stored water. Common materials used for relining include epoxy, polyurethane and polyethylene, chosen for their durability and compatibility with potable water.
Water tanks can experience contamination through internal factors such as corrosion, rust, sediment build-up and bacterial growth. A professional tank lining forms a barrier between the water and the tank’s material, stopping these contaminants from entering the water supply. Instead of refurbishing or replacing a tank completely, relining is a more cost-effective and efficient way to restore protection and hygiene.
- Are you debating between relining and replacing your tank? Read our comparison in Water Tank Lining vs Replacement.
How a Water Tank Lining Prevents Contamination
For tanks that store potable water, preventing contamination is vital. Contaminated water can contain harmful pathogens that pose serious health risks, as well as cause damage to the tank over time.
Creates a Protective Barrier
The main purpose of a tank lining is to form a continuous protective layer inside the tank. This barrier prevents stored water from coming into contact with the tank’s structure. If cracks or small leaks exist, a new lining seals them, keeping out any external contaminants that could compromise water quality.
Protects Against Rust and Corrosion
Metal tanks, particularly steel ones, are prone to oxidation when exposed to water and air, which eventually causes rust. This rust can flake off into the water and cause a contaminated water tank. Tank relining blocks air and moisture, preventing corrosion and ensuring the water remains safe and clear.
Preventing Bacterial Growth
Another key benefit of water tank relining is the prevention of harmful bacteria, including Legionella pneumophila, the bacteria responsible for Legionnaires’ disease. According to the Health and Safety Executive (HSE), outbreaks often occur in water systems where temperatures allow bacteria to multiply, such as hot and cold water tanks, cooling towers and evaporative condensers.
A sealed tank liner eliminates tiny crevices, cracks and rough surfaces where bacteria and biofilms normally cling. When the interior is non-porous and free of defects, there are far fewer places for microbes to harbour and breed, greatly reducing the risk of water tank contamination.
However, lining alone isn’t enough. Seasonal maintenance plays a critical role in controlling bacterial risk, particularly as temperatures begin to rise after winter. Our guide to maintaining commercial water systems in spring explains the key checks that help prevent stagnation, temperature-related bacterial growth and system deterioration.
Extending Tank Lifespan
Older tanks that show signs of corrosion or deterioration are much more likely to harbour bacteria and debris, increasing the risk of contamination. Relining restores the interior, renewing its integrity and providing long-term protection. A well-maintained, lined tank stays hygienic and safe for many years, eliminating the need for early replacement.
Eliminating Sediment Buildup
Water tanks with porous surfaces allow sediment and organic matter to accumulate, which creates ideal conditions for bacteria and algae. A relined surface is smooth and easy to clean, preventing sediment build up and keeping water quality high.
To learn more about how interior coatings work to prevent a contaminated water tank and extend the lifespan of your system, read our guide:
How Water Relining Supports Legal Regulations
Water tank relining helps businesses comply with regulations that prevent water tank contamination and protect public health. The HSE requires organisations to manage and control the risk of Legionella bacteria under the Control of Substances Hazardous to Health (COSHH) Regulations 2002. The Approved Code of Practice (ACOP L8) and HSG274 provide further guidance on controlling Legionella in water systems.
A properly relined tank ensures:
- Surfaces remain smooth and non-porous, preventing bacterial growth.
- Corrosion and leaks are eliminated, reducing contamination risks.
- Water quality tests are more consistent and reliable.
- Systems meet WRAS (Water Regulations Advisory Scheme) approval for materials in contact with drinking water.
By relining your tank, you’re not only maintaining high hygiene standards but also demonstrating due diligence in meeting legal requirements for safe water storage.
Signs That a Water Tank Needs Relining
Water tanks naturally degrade over time. Recognising when relining is needed can prevent serious water hygiene issues. Look out for:
- Rust or discoloured areas inside the tank
- Peeling or flaking coatings
- Cracks, leaks or damp patches on the exterior
- Discoloured water or unusual odours
- Failing water hygiene test results
If any of these issues appear, the tank may already be at risk of contamination. Relining it promptly helps avoid further deterioration and keeps the water supply clean.
Trust Covac to Reline Your Water Tank
At COVAC, we have over 25 years’ hands-on experience protecting water tanks across the UK through tank coating systems. We use WRAS-approved products and every relining job includes a minimum 10-year guarantee on both product and workmanship.
By choosing Covac, you’re choosing:
- Regulatory confidence (meeting HSE, WRAS and DWI standards)
- Proven track record across public, private, healthcare, educational and industrial settings
- Long-term protection and peace of mind
If you want to secure your system and prevent water tank contamination once and for all, contact our experts today.
