After thousands of risk assessments across residential blocks in London and the South East, we see the same issues cropping up time and again. Here are the five most common water system problems we find — and what you can do about them.
Cold water storage tanks on the roof or in the loft are the starting point for much of a building's water supply. If the lid is missing, cracked, poorly fitted, or doesn't have a screened overflow pipe, you're inviting contamination. We regularly find tanks with ill-fitting lids, insect ingress, debris inside, and even bird droppings. Fix: replace or repair the lid, add a screened overflow, and inspect the tank annually.
Dead legs are sections of pipe that are connected to the live system but no longer serve an active outlet. Water sits in these dead legs, stagnating — creating an ideal environment for bacteria. They often occur when a kitchen or bathroom is reconfigured but the old pipework isn't properly removed. Fix: identify and remove dead legs so that all water in the system is flowing regularly.
L8 guidance requires hot water to be stored at 60°C and delivered at 50°C within one minute at the furthest outlet. We frequently find systems where the calorifier is set too low, where heat loss in long pipe runs drops the temperature below safe levels, or where TMVs are reducing the temperature before it reaches the required threshold. Fix: check calorifier settings, insulate pipework, and service TMVs.
Empty flats, unused communal spaces, and seasonal facilities (like rooftop terraces) can have outlets that go weeks or months without being used. Stagnant water in these outlets is a significant Legionella risk. Fix: implement a weekly flushing regime for all low-use outlets, and document it.
Managing agents sometimes inherit buildings where no Legionella risk assessment has ever been done, or where the existing assessment is five or more years old. Without current documentation, you can't demonstrate compliance — and you don't actually know what risks exist in the building. Fix: commission a current risk assessment and set up an ongoing compliance programme with proper record-keeping.
Most of these issues are preventable with a competent risk assessment and a proactive compliance programme. The cost of putting them right is almost always far less than the cost of dealing with a contamination event, an HSE investigation, or a legal claim. If you manage residential blocks and you're not sure about the state of your water systems, the best first step is always a thorough risk assessment.
Manage a residential block? Get a free compliance review to find out where you stand.