AUSTIN (KXAN) — A boil water notice was issued for all Austin Water customers Saturday night due to an “internal treatment process issue that resulted in high turbidity within the [Ullrich Water Treatment] plant.”

You may be asking yourself — what is turbidity?

A 2014-2015 report on the City of Austin’s open data portal says it’s a measurement that indicates the clarity or the clearness of the drinking water. It indicates the presence of suspended solids like clay, silt, plankton or other contaminants.

A bench-top turbidity meter at each of Austin water’s treatment plants measures turbidity every four hours and it is continuously monitored online.

“We have no indication that there was a contamination,” Austin Water Director Greg Meszaros said Saturday night.

Meszaros said the boil water notice is not connected to the winter storm that swept through Central Texas Thursday, calling the timing “coincidental.”

The Austin Water director added that this issue was caused by internal systems and wasn’t connected to river water.

Meszaros said when the utility company experiences a turbidity spike, it must consult with regulatory agencies like the Texas Commission on Environmental Quality. Austin Water leaders spoke with those agencies on Saturday and ultimately decided to issue the notice.