Define Surface Water Treatment Rule (SWTR)

SWTR sets forth primary drinking water regulations requiring treatment of surface water supplies or groundwater supplies under the direct influence of surface water.

a. Require filtration, and/or disinfection (to satisfy the MCLs for turbidity and microorganisms)

b. Turbidity limit (should be less than 0.5 NTU in 95% samples for direct filtration (may vary from state to state and when different filtration is used)

c. Disinfection (99.9 or 3-log removal for giardia or 99.99% or 4-log removal for viruses for filtered or unfiltered water systems)