Water Tank Maintenance

Water Tank Maintenance Plan

Maintenance to your Rainwater Tank and System is crucial to keep your water in premium condition. Every situation requires different attention as there are several factors that need to be accounted for. This check is only relating to the physical water tanks, please ensure that the whole system is checked regularly especially if this rainwater system is for household use

Maintenance of Plastic Water Tanks every 6 to 12 Months water tanks should be visually checked as follows


Action Required

Check water tankfor any undermining of base materials, this can be caused by overflows not being installed correctly or natural water paths flowing through the tanks base area.

Ensure base materials are “boxed in” and that there is an even base all the way around the tanks, normally Gap 7 or sand, in the event of significant undermining the base may need to be repaired.

Check inlet and overflow pipe for brakes, damage or blockages, also check that rubber tank seals are correctly installed.

Have a plumber or drainlayer repair any damages.

Check the overflow pipe is not blocked.

Clean the overflow pipe or outlet of the overflow pipe.

Carefully open the lid of the tank and check internally with a torch to see how much sediment is at the bottom of the tank.

If the silt is greater than about 200mm, the tank should be professionally cleaned by a tank cleaning company.

Check lids firmly attached and prevent wildlife or children from entering the tank.


If lid is damaged, please contact Big Water Tanks ltd for a replacement lid, please photograph your lid and email an order to and we can arrange a replacement lid.

Check tank exterior is clean and free from debris, remove debris around the manhole and/or pipework.


Remove debris (leaves, twigs etc.) from tank, hose off tank or scrub with soapy water if required.

A ladder may be required to access higher areas of tanks and as plastic tanks walls are “slippery” please ensure that someone is supporting the ladder to prevent any injury


Additionally, you should setup a household rainwater maintenance plan for the entire rainwater system:

Check Roof, Gutters, Gutter Filters, Pre-Tank Filters, Water Strainers, Water Filters, Ultraviolet Systems and Water Quality Testing.

Download our: Tank Maintenance Form