Storage tanks and distribution pipework systems are potential sources of contamination, particularly from bacteria. Good design and proper maintenance regimes are needed to minimise problems. The choice of materials of construction is also critical. Metals, other than stainless steel (316L / 1.4435 or 1.4404), should be avoided. There are many high purity plastics (PVDF) available but care needs to be taken to avoid those with fillers and additives which could contaminate the water. Storage tanks should be protected from ingress of contaminants with suitable vent filters. The purified water is recirculated continuously and cooled to maintain purity. UV disinfection is often used to maintain microbial purity in the distribution loop. Disinfection with Ozone is growing in popularity because it is generated in-situ and is twice as powerful an oxidant as chlorine.

Periodic sanitisation with heat is commonly used in pharmaceutical water installations. There are two main methods: hot water and over-heated water. Hot water sanitisation is the most straightforward method by heating up the water to 85°C/185°F and hold it during a validated period of time.