The possible rate hikes come as a result of a federal mandate to protect public water supplies from terrorist attacks. Seattle has responded by burying its reservoirs, which is expensive, but satisfies the mandate and reduces other risks.

"For health reasons, we're covering them," Andy Ryan with Public Utilities said Thursday, while working at a covered reservoir in Maple Leaf.

A Portland reservoir had to be drained recently after a surveillance camera caught a man urinating in it.

The Maple Leaf reservoir is the largest -- and last -- in Seattle to be buried. Next year, there will be 60 million gallons of water in the reservoir and a park on top.

The price for that kind of work -- it cost the city about $142 million to bury four reservoirs -- combined with fewer new homes connecting to the line due to the economic downturn prompted Seattle Utilities' decision to ask for a rate hike.

"Our revenues have not been what we expected them to be ever sine the economy went into a decline," Ryan said.

Public Utilities will reveal the exact amount of the proposed hike Friday, but KIRO 7 has learned that it will be near what a trade publication described as the national average of 9.4 percent each year -- about 28 percent over three years. That would mean a typical Seattle household which now pays about $32 per month would pay almost $40 per month in 2014.

Scott Rubin, a national expert on water rates, described the proposed Seattle hike as "on the higher end" of those he's seen, but said rates everywhere are only headed in one direction.

"It's very rare for water rates to go down," he said. "I'm trying to think of one over the last 25 years and I can't."

Public Utilities said the proposal comes on the heels of the utility laying off 85 people and cutting $57 million from its budget.

"This is a terrible economy and we absolutely sympathize with what's happening with our ratepayers and their personal budgets," Ryan said. "We have scrubbed our budget."

City officials said the good news is that they're nearing the end of making big investments like these.

Any rate increase would require City Council approval. Friday's expected proposal would take effect in January 2012.