Asbestos Cement Water Tank

Asbestos cement water tanks were a standard component of domestic plumbing systems in homes built from the 1940s through to the late 1980s. Positioned in loft spaces or roof voids, these tanks stored cold water for the household's gravity-fed system, feeding bathrooms and hot water cylinders. They were manufactured by pressing a slurry of Portland cement and chrysotile asbestos fibres into rectangular or cylindrical moulds.

The asbestos content in these tanks typically ranges from 10 to 15 per cent, providing the cement with tensile reinforcement and resistance to cracking under the static load of stored water. The tanks were valued for their durability, resistance to corrosion, and the fact that they did not affect water taste or quality — at least according to the standards of the era.

Millions of asbestos cement water tanks were installed in British homes during the post-war housing boom. They are also found in Australian, New Zealand, South African, and Irish properties of similar vintage. Many remain in place today, particularly in homes that have not undergone major plumbing upgrades.

While the tank is intact and holds water, the risk of fibre release is minimal because the cement matrix remains damp and sealed. However, if the tank has been drained, is cracking, or has deteriorated from age, the surface can dry out and begin to release fibres, particularly in a dusty, low-ventilation loft environment. Physical disturbance, such as bumping the tank while accessing the loft, can also cause fragments to break off.

There has been some concern about asbestos fibres leaching into stored drinking water, though evidence suggests this risk is very low for intact tanks. Nevertheless, modern practice recommends replacing asbestos cement tanks with plastic alternatives during any plumbing renovation. A licensed asbestos contractor can remove the old tank safely, preventing fibre release in the confined loft space.