What is UV transmittance (UVT)?
UV transmittance (UVT) measures water’s ability to transmit UV light. The majority of deep wells have a UVT of about 85% or greater and most of municipal water supply have about 95% UVT. Surface water such as lakes, streams, ponds, springs may have about 75% UVT. Water with a lower UVT will require a larger UV system to deliver the disinfection performance required. Therefore, we recommend pre-treating water that has less than 75% UVT as it will affect the dosage* your UV system is capable of producing.
