WYLIE, Texas (CBSDFW.COM) – Thousands of gallons of wastewater spilled at the North Texas Municipal Water District’s site, which eventually flowed into the far northwest area of a lake, district officials say.

The water district had a release of domestic wastewater from the Wilson Creek Regional Wastewater Plant in Allen that wasn’t fully treated.

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According to district officials, the discharge happened Wednesday during a heavy thunderstorm and power outage. The treatment process wasn’t completed because of the power outage.

A little under 28,000 gallons of wastewater spilled at the site and eventually flowed into Lavon Lake.

“It is unbelievable that they could dump that much crap into the water,” said Joel Ledbetter, who saw the waste being dumped.

Ledbetter said he was fishing when he started smelling sewage.

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“So I went around the bend from where I was fishing from and there was just mats, layers, islands of sewage just floating in the lake,” said Ledbetter.

The water district crews have been sent to the lake to clean up the water. District officials said they have notified government agencies.

Ledbetter said he was told it wasn’t raw sewage; however, he saw condoms, drug bags, toilet paper and a water district hard hat.

“If it was good sewage that wasn’t going to be a problem, I don’t know why today they would come out and start cleaning it up,” said Ledbetter.

The water district has provided treated drinking water. District officials warn that people using private drinking water supply wells within one-half of a mile of the spill site should distill or boil their water.

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They warn the public should avoid contact with the waste material in the lake and anyone who has come in contact with it should bathe and wash their clothes thoroughly and as soon as possible.