Dry conditions are causing isolated problems in some municipal and household water systems in southern Maine, which experts say is in the midst of a moderate to severe drought.

Although weekend storms could revive browning lawns and raise water levels in parched streams, the rainfall is unlikely to make much of a long-term dent in the months-long drought.

“We don’t need short, little thunderstorms. We need a soaking rain for several days, especially for groundwater” supplies, said Nick Stasulis, data section chief for the U.S. Geological Survey in Maine. “Most of our groundwater comes from snowmelt and we didn’t have a significant snowpack this year.”

One southern Maine town issued a water quality advisory this week after drought-related conditions turned the water a blackish color.

On Wednesday, Berwick officials advised parents with young children to switch to bottled water because of elevated manganese levels in the town water supply. A naturally occurring mineral, manganese typically only causes aesthetic problems – such as color and odor – but has been linked to developmental and neurological problems in children exposed to the mineral at extremely high levels.

The town is exploring options for removing the manganese from the water – including additional filtration – but is now working with water bottler Poland Spring to supply free gallon jugs of water to townspeople. Stephen Eldridge, Berwick’s town manager, is hoping Poland Spring will donate the water, but said the town is still talking with the company about compensation.

Eldridge said concentrations of manganese have risen in the source of the town’s water, the Salmon Falls River, due to the drought. That has led to discolored and odoriferous water that is safe to drink, according to Maine Department of Health and Humans Services guidelines, but that is unappealing for most people.

“We are taking precautions and making sure everyone is aware of it, and believe me they are,” Eldridge said.

Maine state geologist Robert Marvinney said many public water systems are able to handle these types of extended dry conditions because they worked to diversify their sources since the severe drought of 2001-02. During that drought, 35 public water suppliers – including eight larger systems – were “severely” affected by the drought and an estimated 17,000 private wells in Maine ran dry, according to an analysis prepared for a special drought task force.

“For the most part, public water systems haven’t been reporting problems,” Marvinney said. “It’s no surprise there are spotty problems here and there, though, particularly in southern Maine.”

Homeowners who rely on shallower dug wells for their water – rather than drilled wells that extend into the bedrock – in some areas could experience problems in such conditions. But Marvinney said many homeowners replaced dug wells with drilled wells following the last drought, and most new construction since then would feature drilled wells.

Roughly half of Maine’s population is living in areas facing drought conditions.

Much of York County and the southern portion of Cumberland County extending to the northern suburbs of Portland are in the midst of a “severe drought,” according to the U.S. Drought Monitor program operated by the National Drought Mitigation Center. “Severe drought” is the third-highest classification system that ranges from “abnormally dry” to “exceptional drought.” Much of the rest of southern and midcoast Maine is under a “moderate drought,” while conditions are considered “abnormally dry” throughout western, central and Down East Maine.

Roughly 60 percent of the Northeast was under some drought condition. A small area of Massachusetts northwest of Boston is experiencing “extreme drought,” a first for the state since the national monitoring program began in 1999.

“If you look at how often this level of drought occurs in that area, it’s once every 20 or 25 years,” Mark Svoboda, a climatologist with the National Drought Mitigation Center at the University of Nebraska, told the Associated Press.

Maine’s waterways also tell an austere story.

Earlier this week, rivers and streams from Kittery to the Katahdin region were running so low compared to their historical streamflow that they were considered by the USGS to be in a “severe hydrologic drought.” The streamflow in the watersheds for several of the state’s major river systems – including the Penobscot, Kennebec and Piscataquis rivers – were in “extreme hydrologic drought.”

That means the streamflow on that particular date was lower than all but a handful of years since monitoring began, with records stretching back more than a century for many rivers and streams.

Stasulis, with the USGS, said homeowners with private wells should start thinking about their water usage, especially if the abnormally dry conditions continue into the fall and winter. That’s because once the snow starts to fall, underground aquifers are unlikely to be recharged until the spring.

“I’m certainly not running the sprinkler and the Slip ‘N Slide for my daughter everyday,” said Stasulis, whose home is on well water. “We should start thinking about groundwater use if you’re on a private well and, as best you reasonably can, conserve water, which we should be doing anyway.”

Reports suggest that well drilling companies have been busy responding to homeowners concerned about their wells. One company owner contacted Thursday said the small firm already was so busy responding to calls – often just from worried well owners not yet experiencing water problems – that he didn’t even want the company’s name in the paper for fear of generating additional calls.

Groundwater levels are lower than normal throughout the region. One Sanford well monitored by the USGS has been lower in July and August than it has ever been during those months since monitoring began in 1989.

But Sanford Water District Superintendent David Parent said local residents need not worry about the town’s water supply, which has nine separate sources.

“Our wells are a little low – probably two to three feet low – but there is still a lot of storage in the aquifer so we are in pretty good shape,” Parent said.