Concrete, Plastic and Fiberglass Water Tanks: How the Cleaning Method Differs

Concrete contains fine pores where sediment and algae cling, so the crew needs longer scrubbing and must remove the whole sediment layer from the walls and floor rather than only draining and rinsing.

Over the years concrete loses some of its waterproofing and hairline cracks or damp patches appear. These can signal outside water seeping in or inside water seeping out, and they deserve to be recorded and repaired.

After cleaning, surfaces should dry slightly and then be inspected, because wet surfaces hide defects. Ask the crew to show you the corners, which collect the most sediment.

Plastic roof tanks are popular because they are light and easy to install. The smooth surface makes sediment easier to remove, but rough metal tools scratch it, and scratches later become footholds for algae.

Soft brushes and non-abrasive cloths are preferred, and very hot water should be avoided because it can soften the plastic. Tank color matters too: dark colors block light and limit algae compared with pale ones.

Under Jeddah's strong sun, unprotected plastic can become brittle over the years, so inspect the exterior for cracks, fading and weld lines around the openings.

A fiberglass tank is durable but carries a smooth inner coating that protects it and stops sediment from sticking. Hard scrubbing or sharp tools can remove part of that coating, leaving a rough surface that collects dirt faster.

Cleaning is therefore limited to soft brushes and solutions suitable for drinking water. If you notice peeling or dark patches that stay attached, the coating is weakening and a specialist opinion is needed.

Avoid any product of unknown composition, because residue on porous fiberglass can end up in drinking water.

Metal tanks, whether coated or stainless, need watching at welds and joints where rust starts. Rust changes the color and taste of water and signals corrosion that cleaning alone cannot fix.

Strong cleaners can damage the coating or speed up corrosion, so products must suit the metal and be safe for drinking water, followed by thorough rinsing.

If rust spots return after every cleaning, ask about repairing the coating or replacing the corroded section instead of cleaning repeatedly.

Some concrete tanks carry a waterproof lining or a paint made for drinking water. That layer protects the concrete and stops its components from leaching into the water, but it ages and can peel.

Before any cleaning, ask when the lining was applied. If it is peeling or blistering, ordinary cleaning will not solve the problem and could worsen it if part of the layer is scrubbed away.

Keep renewal and cleaning dates in one file. It helps you decide on maintenance before the problem becomes a leak or contamination.

There is no single recipe for every material. What matters most is that products are suitable for drinking water, that they are fully rinsed away, and that the contact time recommended by the product maker is respected.

Ask the crew which products they use and how they handle the final rinse, and whether the tank is checked for odor afterwards. A clear answer shows an organized operation; vagueness is a warning sign.

Never mix cleaners yourself inside the tank or at the opening, because some mixtures release harmful gases in an enclosed space.

Whatever the material, working inside a tank is confined-space work with limited ventilation and risks such as slipping, low oxygen and cleaner fumes. Do not enter a tank yourself without training and equipment.

A professional team arranges ventilation, uses protective gear and keeps an observer outside the tank. Ask about these procedures when choosing a company, as they are a good sign of seriousness.

Keep children and family away from the tank area during the work and close the access point securely afterwards.