In a rare dose of good news, residents of a troubled water and sewer district at Lake Berryessa learned Tuesday they were approved for an $8.1 million loan from the federal government to pay for direly needed infrastructure improvements.

Getting the loan was another crucial hurdle for the district, which serves about 350 homes in Berryessa Highlands on the south side of the lake, to get into compliance with state water quality regulators.

The residents voted in July to form an assessment district to pay for the improvement project, which improves the district’s water and wastewater systems.

State regulators had penalized the district for discharging treated wastewater into the lake during periods of heavy rainfall; the improvements will stop those discharges.

The loan, from the U.S. Department of Agriculture, should allow for construction to begin next spring on the district’s sewer system, with the goal of finishing before the rains return in the fall of 2013, Napa County Deputy Public Works Director Phil Miller said Tuesday.

Miller delivered the news at a meeting of the board of directors for the district, called the Napa Berryessa Resort Improvement District. His announcement was met with applause.

The county Board of Supervisors acts as the district’s board of directors, and the county’s Public Works Department operates the district’s systems.

“This was wonderful news,” said Highlands resident Stu Williams. “I think it was a relief for all of us today.”

Miller said the district is still waiting to hear on a loan application to the USDA that would cover the remainder of the total project cost of $11.1 million. He said the USDA splits up the loans between water and sewer components. The sewer part of the project is covered by the $8 million loan.

Residents of the district will repay that loan through the property assessment they approved in July.

Getting the USDA loan will allow for the highest priority projects — expanding the storage ponds and other methods of stopping the wastewater discharges — to be completed next year.

Last fall, the Central Valley Regional Water Quality Control Board slapped the district with a $330,000 fine for discharges that occurred in 2010 and 2011. Through negotiations, the district was able to greatly reduce that fine and use savings to pay for the improvements.

The district still owes the state a $95,000 fine, and the board voted Tuesday to loan the district that amount.

The settlement agreement also spelled out a schedule for completing the improvements. The district won’t be penalized for any discharges this fall and winter, but has to have the upgraded wastewater treatment plant operational by Nov. 30, 2013, according to the settlement agreement.

Miller said Tuesday that the district has about six months worth of work to complete. The goal is to start in April and finish by October.

Miller credited the work of staff on the loan application, while Williams thanked the efforts of officials like U.S. Rep. Mike Thompson, D-St. Helena, U.S. Sen. Dianne Feinstein, D-Calif., and the county supervisors.

“You’ll be seeing a press release on this,” Miller told the board Tuesday morning.

“We should be throwing a party,” Supervisor Keith Caldwell replied.