Raw water systems and their components, including mechanical cooling systems, fire prevention systems, screens, and valves are susceptible to zebra mussel infestations. These systems are particularly susceptible if they leak or are used periodically (once every several days or weeks) and, therefore, do not become stagnant. Zebra mussels can foul the intake screens and piping of these systems preventing normal operation and leading to equipment damage. Control methods applicable to raw water systems include the use of non-contaminated (commercial or ground well) water, regular backflushing or backflushing using water heated above 38° C, storing lines in the dry during periods of non-use, chemical treatment (e.g., chlorination), and minimizing leakage so that lines become anoxic.