LAS VEGAS (KLAS) — A manhole near a Las Vegas sewage facility overflowed for more than two days before crews noticed, found its cause and then stopped the nearly 900,000-gallon discharge, documents the 8 News Now Investigators obtained Thursday said.

The 8 News Now Investigators first alerted the Clark County Water Reclamation District to potential problems at the Whitney Lift Station in 2021. In 2020, the facility, which sits at a low point in the southeast Las Vegas valley near Sam Boyd Stadium, failed.

The 2021 failure caused an estimated half-million gallons of wastewater — some of which ended up in a creek that feeds Lake Mead — to spill.

Around 9 a.m. on Thursday, June 1, a piece of equipment at the station failed, causing nearly 900,000 gallons of untreated sewage to overflow, documents the 8 News Now Investigators first obtained Tuesday said.

Crews did not know about overflow until 1 p.m. on Saturday, June 3, documents said. The manhole is outside of the facility’s fence line and “outside the view of CCWRD staff,” documents said. A partially closed value between the lift station and a rock catcher caused the spill, documents said.

Crews recovered nearly 300,000 gallons of raw discharge, leaving about 600,000 gallons to go into the creek or seep into the ground, documents indicated. On Thursday, CCWRD said it estimates about 60,000 gallons traveled into the creek, which feeds the Las Vegas Wash and Lake Mead.

A half-million gallons are almost enough to fill an Olympic-sized swimming pool. The reclamation district handles 100 million gallons a day.

Testing in the creek did not show elevated bacteria concentrations from the sewage, the reclamation district said. The Environmental Protection Agency said it was aware of last week’s spill. A spokesperson for the Southern Nevada Health District said the department was also aware.

The 2020 spill was blamed on a corroded underground pipe. Teams caught about 300,000 gallons of raw sewage, sucking it up with special vacuums. The rest seeped into the ground. An estimated 10,000 gallons poured into the creek.

The district board of trustees, which is the same body as the Clark County Commission, approved a multi-million-dollar rehabilitation project for the lift station. In 2021, the board described the station as “the largest and most critical lift station in our service area in terms of capacity, location, engineering hydraulic requirements and necessary operational efficiencies.”

“I am monitoring the situation and working closely with stakeholders on the ground,” Democratic Rep. Dina Titus tweeted Tuesday citing the 8 News Now Investigators’ reporting. “We must ensure that southern Nevadans have access to water quality as well as quantity.”

Clark County’s water quality program, which would fine the district, reports to the district. The program’s offices are in the district’s headquarters, too.

The district requested 8 News Now not identify the lift station’s exact location, citing homeland security laws.