Is it Cheaper to Reline a Water Tank or Replace it?

For facilities managers responsible for the upkeep of commercial or industrial buildings, water storage maintenance is a constant balancing act between cost, safety, and regulatory compliance. Over time, even the best-designed cold water storage systems begin to show signs of age - from internal corrosion to leaks and general wear and tear.

When this happens, the question naturally arises: Should you reline the tank or replace it altogether? In this guide, we’ll walk you through the key considerations, costs, and compliance implications to help you make a well-informed decision.

Understanding Water Tank Relining

What Is Water Tank Relining?

Water tank relining involves applying a new internal coating to an existing tank -often using WRAS-approved polyurethane or epoxy lining materials. This refurbishment process restores the tank’s protective layer, safeguards against corrosion, and improves water hygiene without removing or replacing the entire unit.

It’s a proven solution for tanks that are still structurally sound but have begun to degrade internally.

What Are the Advantages of Tank Lining?

• Cost-Effective Remediation

  Relining is generally cheaper than full tank replacement. It eliminates the need for dismantling the old structure, managing waste, or purchasing a new cold water tank.

  
  

• Reduced Downtime

  Many relining jobs can be completed in fewer days, depending on tank size and condition. This minimises disruption to operations, especially in critical environments like hospitals or manufacturing sites.

  
  

• Improved Water Quality

  Modern lining systems can improve resistance to biofilm growth, helping to reduce legionella risk and enhance overall water hygiene.

  
  

• Compliance and Peace of Mind

  Most reputable contractors use materials that meet HSE and WRAS standards, supporting compliance with ACOP L8 and water regulations in the UK.

Want to understand the process step by step? Visit our page on How to Reline a Water Tank.

When Tank Replacement Is the Better Option

Red Flags That Call for a New Tank

There are times when relining simply won’t cut it. Full replacement may be required if:

• The Tank Has Severe Structural Damage

  Major cracks, failing seals, warped base or walls are all key indicators that the tank is no longer mechanically sound.

  
  

• Extensive Corrosion or Delamination

  Especially in steel and GRP tanks, deep-set corrosion or breakdown of fibreglass layers may be beyond repair.

  
  

• Outdated Design or Capacity

  Older tanks may lack thermal insulation, access hatches, or the correct internal baffling to meet modern water hygiene standards.

  
  

• Non-Compliance or Access Risks

  Tanks that require confined space entry or cannot be made compliant with minimal intervention may be better replaced.

Learn more about our Cold Water Tank Installation Services if you're considering a replacement.

Comparing the Costs: Relining vs. Replacing

What You Might Pay — And What to Expect

Here's a cost breakdown for a recent project where we provided the customer with a price for both options, highlighting the difference you can expect.

Both options included the supply and installation of a a temporary tank. The tank we were quoting to reline / replace was a sectional GRP tank with dimensions of 2.5m x 2m x 3m:

• Relining

  £17,450 - Includes surface preparation, lining, curing, and compliance testing, and comes with a 10 year guarantee.

  
  

• Replacement

  £29,590 - Includes removal, disposal, supply and installation of new tank, pipework adaptation, commissioning. Project comes with a 12 month warranty.

Relining is almost always cheaper upfront, but don’t overlook life expectancy. A high-quality new tank may last 25+ years with minimal maintenance, whereas relining may need to be repeated in 10 - 20 years, depending on use.

Other Factors to Consider

Is Relining Always an Option?

Not necessarily. Your existing tank must pass a structural and risk assessment before relining. This includes checks for:

• Integrity of baffle walls and lid

• Leak detection or seepage

• Compatibility of lining materials

• Accessibility for safe application

Tanks located in tight plant rooms or with limited safe access may complicate the process. In such cases, a new tank with better positioning might offer long-term benefits.

Final Thoughts: What’s Right for Your Site?

Choosing between relining and replacing a water tank isn’t always straightforward. Here’s a quick reference to help guide your decision:

Factor	Reline	Replace
Cost	Lower	Higher
Downtime	Minimal	Longer
Lifespan (typical)	10–20 years	20–30+ years
Compliance Support	Yes (if WRAS)	Yes (modern tanks)
Best for…	Structurally sound tanks needing refurbishment	Severely corroded or outdated systems

Still unsure? Let our specialists evaluate your current system. We can advise you on what’s technically suitable, cost-effective, and compliant with all the right legislation.

Want to Learn More?

Explore our Learning Centre for more guides on cold water storage, water hygiene, and maintenance best practices - all tailored for facilities and estates teams.

For a detailed look at how relining works in practice, check out our dedicated section on Water Tank Relining Services.

Need a closer look at your own tank system? Get in touch to book a review and make an informed decision backed by expert advice.