Austin Water officials reported Wednesday afternoon that the contamination level in the city’s water system has started to drop but the timeline of lifting the boil water notice remains at the whim of Mother Nature.

The issue, officials have said, is the extraordinary amount of sediment that continues to carry into Austin’s water source after weeks of heavy and consistent rainfall sparked destructive floods upstream in the Hill Country. The sediment has forced a heavier workload on Austin’s three water treatment plants and has slowed the city’s daily clean water output to roughly one third. Officials said the sediment levels reached 8,000 percent of what is typical.

Austin Water Director Greg Meszaros said Wednesday that contamination levels had dropped since the city issued a mandatory water boil notice Wednesday morning. However, Meszaros maintained that whether the boil water notice is lifted by the weekend depends on the weather.

“If the rain upsets the water again, that is something we’ll have to take into account [in a decision on the boil water notice],” Meszaros said.

Although the weather is out of Austin’s control, Meszaros said the city’s water consumption is not and continued to urge residents to cut back on usage. On Tuesday, Austinites answered the call and cut usage by between 15 and 20 percent, Meszaros said.

Water contamination levels back below state limit

On Tuesday, City Manager Spencer Cronk said the boil water notice issued Monday was “absolutely precautionary” and no tests indicated that water contamination was above the legal limit; however, the city alerted Austinites early Wednesday morning that contamination levels exceeded the state limit and the boil water notice was elevated to mandatory.

Meszaros said a test taken Tuesday night showed turbidity levels—a measure of sediment and cloudiness in water—had reached the state limit of 5 units and triggered the mandatory boil notice. By Wednesday afternoon, Meszaros said those levels had dropped back below the legal limit but continued to call for a residents to boil their tap water before consumption.

For more water coverage, check out why experts say there was no way to plan for the water emergency, where water is being distributed and what local hospitals are doing during the boil water notice.