Most water problems that persist do so for one reason: the pipework is never cleaned, only the water in it is dosed.
A dose that clears the water column can leave the deposits on the pipe walls untouched, and those deposits shelter the organisms that reseed the system as soon as the dose falls away. Chlorine-based routines can run for years without ever addressing the source. The result is recurring Legionella and pathogen risk, failed tests and rising chemical cost.
In wastewater, the same conventional approach is energy-hungry and chemical-heavy, with aeration alone taking 45 to 75% of a plant's energy, while effluent consents keep tightening.
The cost is paid twice: in the chemicals and energy spent, and in the risk and compliance exposure that remains.