Most utilities in Virginia add fluoride to drinking water to help prevent tooth decay. But in much of western Tidewater — unlike anywhere else in the mid-Atlantic — groundwater tapped by thousands of homes and businesses contains so much fluoride that it can stain teeth brown.

To combat this unflattering condition, called fluorosis, and to reduce other risks, the Virginia Department of Health has ordered 57 water suppliers to cut fluoride levels and comply with a national safe-water standard unheeded locally for the past 15 years.

The state order, affecting more than 23,000 customers, mostly in Suffolk and Isle of Wight County, is expected to cost millions of dollars, increase water rates and involve years of engineering and renovation.

The largest effects will be felt in the city of Franklin, where municipal wells serving all 8,000 residents must be improved. The project pushed water rates up 18 percent this year and likely will increase them another 10 percent to 20 percent in coming years, said Jaime Weist, city public works director.

The move does not touch the larger cities of Hampton Roads, such as Norfolk, Virginia Beach and Chesapeake, which draw their drinking water from lakes. These cities add fluoride to their surface waters to fight tooth decay.

But just to the west, in rural towns and developing counties, tap water comes almost entirely from the ground. Some local residents are thrilled by the state order, saying they have badgered health officials in vain for years to fix a problem with links to brittle bones, ugly teeth and a potentially fatal disease called crippling skeletal fluorosis.

Stained teeth may be a cosmetic problem, but it can be devastating to self-esteem. Lakindra Bowden, 22, a lifelong Smithfield resident, said she never used to smile because of her brown, spotted teeth.

“It was very hard for me,” said Bowden, who recently underwent dental treatments to remove the stains. “I was very self-conscious. When I’d feel myself about to laugh, I’d cover my mouth.”

Other residents oppose the state-mandated water changes. They say their well water prevents tooth decay naturally because of the high fluoride and only causes staining if consumed by infants and small children with immature teeth.

Furthermore, many of the region’s small water systems, owned by civic groups or private companies, will have trouble financing expensive filters or connecting to public utilities, officials say. Rates here will likely go sky-high.

“I’ve got two kids — 27 and 31 years old — and they’ve never had a cavity,” said Wayne Rountree, director of utilities for Isle of Wight County, which must upgrade six of its wells under the state order. “This is not the most necessary thing for us to be doing.”

For this reason, the state for 20 years exempted more than 150 water systems in Western Tidewater from meeting the national fluoride standard, established in 1986 at 4 parts per million. Health officials figured the expected health benefits from screening out fluoride simply did not justify the high cost.

“We didn’t believe there was a cost-effective alternative out there,” said Dan Horne, engineering field director for the state Health Department in Hampton Roads. “We still don’t, really. It just didn’t make practical sense to us.”

But under pressure from the U.S. Environmental Protection Agency, the Health Department last summer and fall began informing 57 of these suppliers — large and small, public and private, all with average levels of more than 4 parts per million — that their exemptions are over.

The violation notices do not include penalties or deadlines. And the state has hired the Hampton Roads Planning District Commission to study the problem and recommend solutions to affected utilities. The work should be completed by the end of the year, said John Carlock, an environmental planner overseeing the study.

Full compliance could be a decade away, experts and officials say. “As long as we continue to see progress, that’s fine,” said Roy Seneca, an EPA spokesman in Philadelphia.

High fluoride is the product of a rare geological feature, seen only in southeast Virginia, Nebraska, Texas and parts of several Pacific Northwest states, according to experts.

Locally, it stems from glauconite sand deposits lying within underground aquifers. When wells are sunk into these aquifers, fluoride is released.

Drilling around the deposits is tricky. If a well is too shallow, it can pick up pollutants that have seeped just below the surface. If it’s drilled too deep, water quality can suffer and cost too much.

Most utilities across the nation will add fluoride so drinking water contains about 1 part per million. The EPA’s national standard requires public notices be sent to customers who receive water with levels between 2 and 4 parts per million.

Typically, groundwater in Western Tidewater contains fluoride between 2 and 5 parts per million, with a few systems climbing above 6 parts per million.

Robert B. Taylor, director of the water supply division of the state Health Department, said chronic exposure to water above 6 parts per million “can get you into a situation where fluoride affects bone structure, especially in the elderly.” This means brittle bones.

Crippling skeletal fluorosis is a rare and potentially deadly disorder that can result from drinking water above 10 parts per million for an estimated 50 years, Taylor said. No such case has ever been recorded in Virginia, he added.

Ted Christian, owner of C&P Suffolk Water Co. in Smithfield, runs 12 systems requiring improvements. They serve subdivisions in Suffolk and Isle of Wight County.

His network includes the Holland Water System, which the state Health Department recognizes as distributing the highest fluoride-containing water in the region, at 6.22 parts per million. (The Hampton Roads Planning District Commission, in its analysis, found the highest fluoride concentration at Nottoway Trailer Park in Southampton County, at 6.51 parts per million.) Christian has discovered that blending water tapped from wells drilled to differing depths — one high, one low — usually drops fluoride readings to below 4 parts per million. He hopes to use this technique at Holland, though he still is exploring all options, including the possibility of connecting to the city of Suffolk.

“The smaller the system, the harder to comply,” Christian said. Cities like Suffolk can raise rates on their own to pay for improvements; private companies need approval from the State Corporation Commission, a difficult and extensive process, he said.

In 1994, seeing the fluoride issue moving to the forefront, Christian branched into another business — selling bottled water. He now offers jugs of spring-fed water, gathered from artesian wells near South Boston, to his groundwater customers at a discount rate.

“It’s the best short-term fix,” he said, referring to the bottled water. “We recommend that people with small children buy this.” Wilson Ames Jr., a dentist in downtown Smithfield, has been helping patients with stained teeth since the 1960s. It is a fairly common ailment in the area, he said, though fluorosis “was a lot worse in my father’s time.”

The senior Ames, also a dentist, first offered a bleaching-type remedy to locals in Smithfield and surrounding Isle of Wight County in the 1930s.

“You can take it off fairly easily,” Ames Jr. explained from his Main Street office last week. He shaves off a sliver of stained enamel with a diamond-tipped instrument, a painless procedure that takes about 30 minutes.

Slight discoloration may remain, so patients also can bleach their teeth, though the technique is more expensive.

Ames does not give fluoride treatments to his young patients. There’s no need, he says. Ames still quarrels with pediatricians who recommend that children take fluoride supplements with their diet. There is no need for that either, he says.

Ames also recommends that parents of young children buy bottled water until their kids reach at least 6 years of age. “Once the enamel is formed, it’s no problem,” he said.

As a child, “my dad used to collect rainwater, then boil it and make me drink that,” Ames said in explaining how he avoided stained teeth during an era when bottled water did not exist.

One of his patients is Bowden, the 22-year-old Smithfield resident and a recent Old Dominion University graduate. To her, there was no choice but to seek dental help.

“I look at all my old pictures, from high school and elementary school and stuff, and I’m not smiling in any of them,” Bowden said. Peers would make fun of her, she said, and ask if she was a smoker.

Bowden underwent the shaving procedure about a month ago, and “I feel much better about myself.” Still, she wants to get her teeth bleached, like her aunt, to erase some lingering yellow. She’s saving money for the treatment now, and worries that her 19-month-old son may go through a similar ordeal.

“He gets bottled water, but I mean, you still brush your teeth in it. I’m very concerned for him and the other young kids who live here,” she said.