Water tanks

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Your trusted, local same-day plumbers

Some of our recent work....

Leaking loft cold water tank.

Water tank replacement.

Caversham customer – KK.

KK noticed a small but increasing damp patch one the ceiling of one of his home’s bedrooms. Investigating, he went into the loft and saw that there was trickle of water coming from the back corner of the mains fed cold water tank.

Getting in touch, we were with him within 30 minutes. The tank was patched temporarily on the inside and outside stoping the water flow. A new 50 gallon tank was ordered, and installed the following day and the old tank removed and disposed off.

Water tank cleaning and sanitisation.

Reading customer – Richard.

Richard asked us to help with the renovation of two houses. The second had been used for storage and unoccupied for some time. The central heating system was intact but not working.

As a pre-course to it being serviced, the cold water and feed and expansion tanks were drained, cleaned and sanitised. Both the cold water and hot water systems were also drained and flushed with inhibitor added to the F&E tank to protect the boiler and heating.

The quickest way to get in touch to discuss repairing, replacing or sanitising your home’s water tanks is to WhatsApp, text or phone us on 07442966664.

You can also email plumbing@angusplumbing.co.uk or use the form – and well get back to you as soon as we can.

The AngusPLUMBING team

Water tanks

Loft water tanks, also known as cold water storage cisterns or header tanks (feed and expansion), are typically installed in the attic to store cold water and create pressure via gravity for a home’s plumbing and central heating systems. Modern tanks are made from polyethylene plastic or GRP (Glass Reinforced Plastic), which are durable, lightweight, and resistant to rust and microbial growth.

Types and materials

Loft water tanks come in a few primary types designed for different installation needs:

One-piece tanks: Pre-moulded and ready for installation, ideal for most residential applications where space and access are not major issues.
Sectional tanks: Made from modular panels, allowing for easy transport and assembly in restricted loft spaces, typically used for larger capacity requirements.
“Coffin” tanks: Characterised by their long, narrow shape, designed to fit into tight, awkward loft spaces.

The main material used today is polyethylene plastic, often black to prevent light ingress (which inhibits algae growth), and it is typically WRAS (Water Regulations Advisory Scheme) approved for storing potable (drinking) water. Older homes may still have galvanised iron or steel tanks, which are prone to rust and corrosion and should be replaced with a modern plastic alternative.

Regulations and maintenance

UK regulations are primarily focused on maintaining water quality and preventing contamination:

WRAS approval: All components in contact with potable water must be WRAS approved.
Secure lids: The tank must have a tightly fitting lid that excludes light and prevents the ingress of birds, vermin, and dust.
Screened vents: Vents and overflow pipes must be screened to prevent insects and particles from entering the tank.
Insulation: The tank should be insulated to keep the water as cold as practicable and prevent freezing in winter, and it should not be located near a heat source.
Regular inspection: Periodic visual checks are essential (at least annually for non-potable water, and every 6 months for drinking water) to check for scale, debris, and secure fittings.

Water tank repair

Many common loft water tank issues can be fixed with DIY methods like replacing a faulty ball valve or sealing small cracks with epoxy. However, severe damage like large cracks or a compromised structure may require professional replacement.

Common repairs and DIY fixes

Leaking overflow pipe: This is typically caused by a faulty ball valve not shutting off the water supply correctly, causing the tank to overfill.

DIY fix: Check if the float ball is waterlogged or misaligned. If the internal mechanism is worn, you can replace the entire ball valve assembly with a Part 2 valve.
Cracks or pinhole leaks (plastic tanks): Small cracks can develop over time due to age, fluctuating temperatures, or impact.

DIY fix: Ensure the tank is drained and dry. For a temporary fix, clean and sand the area, then apply a waterproof epoxy putty like J-B Weld WaterWeld Epoxy Putty 57g. For a more durable repair, use a plastic welding kit with a heat gun or soldering iron to fuse compatible plastic rods into the crack.
Sediment buildup: Minerals, dirt, and debris can accumulate at the bottom of the tank, reducing capacity and potentially blocking pipes.

DIY fix: Periodically drain and rinse the tank to remove sediment. Installing a filter on the inlet can help prevent future buildup.
Pest intrusion: Unscreened openings can allow pests to enter the tank.

DIY fix: Install fine-mesh screens over all inlet, outlet, and vent openings. Ensure the lid is properly sealed.

When to call a plumber

With some small repairs manageable, some situations are best handled by a professional to ensure safety and compliance with regulations:

Large or multiple cracks: If damage covers a significant portion of the tank or is near a seam, the structural integrity is compromised, and the tank should be replaced.
Deformed or warped tanks: This indicates the structure is fundamentally weakened and needs replacement.
Metal tank corrosion: Old galvanised tanks that are corroded should be replaced, as repairs may not hold and the water quality may be affected.
Accessibility issues: If the source of the leak is difficult to reach or requires specific tools like plastic welding equipment that you are not comfortable using.

Other plumbing services....

Our local plumbers provide a range of expert plumbing services that’ll keep you and your family safe, save you money and your home running smoothly and as it should including:

Improving water pressure and flow (to see our work click here).
Leak detection (to see our work click here).

Water and waste pipe repair & maintenance (to see our work click here).

Unblocking waste systems (to see our work click here).

Dripping/running overflow pipe investigation (to see our work click here).
Turning off/isolating your homes water supply (to see our work click here).
Repairing and maintaining your home’s water tanks (to see our work click here).