The water is safe to drink again in Oak Bluffs after the state Department of Environmental Protection lifted a boil-water order early last Friday, but questions remain about the town’s handling of the situation and its ability to disseminate information during an emergency.

Just after 9 a.m. last Friday the DEP told the town it passed three consecutive days of water testing and formally lifted the boil-water order it had imposed on Sept. 25. The good news capped nearly a full week of confusion and complaints, as residents were forced to use bottled or boiled water for nearly all their needs.

Many residents said they did not learn of the boil-water order until several days after the fact, and some questioned why the town did not have a plan in place to get information to the public in a more timely manner. In response to these complaints, town officials have acknowledged their shortcomings.

“Could we have done a better job? — the answer is yes. I don’t think anyone is denying that,” said Michael deBettencourt, chairman of the water commission. “What we will do now is figure out how to handle this better next time.

“We never really had a plan in place for this type of thing,” he continued. “This was an unfortunate event, but we will learn from this and get better.”

The problem began on Sept. 24 when routine monthly sampling of the town water system showed the presence of coliform bacteria in several samples. Coliform bacteria are naturally present in the environment and are indicators that other, potentially more harmful bacteria may be present that can only be detected with further testing.

Coliform bacteria does pose a health risk to people with compromised immune systems, some elderly people and infants.

Mr. deBettencourt said water officials are now working to determine the source of the coliform bacteria. One theory is that the problem was caused by low water levels tied to the recent departure of a large number of summer residents and visitors.

Fewer users means less water is drawn from town wells, he said. This leads to less water in the town tanks, which could lead to bacteria growing on the side of the walls. But Mr. deBettencourt emphasized this was only a theory. “That’s one of several theories. The truth is, we may never know where the bacteria came from,” he said.

He said the water commission has not discussed whether users will receive a rebate on their water bills. For now the commission is working with selectmen, the board of health and other town officials to develop a detailed plan to inform the public about water contamination in the future.

He said the commission will also consider a plan for regularly flushing the water system, which could reduce the risk of contamination in stagnant water.

Water superintendent Thomas Deg-nan said he is currently working on a report for the DEP that will provide a detailed chronology of the crisis, starting with the water testing that revealed coliform bacteria in the water supply. “It’s basically like a police investigation report, we have to provide them with every piece of information available to try and figure out what happened,” he said.

He warned that the town water supply will contain elevated levels of chlorine for some time, and he said users who are sensitive to chlorine should remain cautious.

Town administrator Michael Dutton said a meeting was held on Tuesday with water officials, emergency management coordinator Peter Martell, health agent Shirley Fauteux and selectman and board chairman Greg Coogan to discuss what will done to alert the public in the future to problems with the town water supply or other emergencies.

Mr. Dutton said a number of ideas were discussed, including creating a list of e-mails for town residents, as well as a reverse 911 system that would allow the Dukes County communications center to call every phone number in town with a prerecorded message alerting them to possible danger.

The e-mail idea came from the owners of Sharky’s Cantina, who sent out e-mail blasts and text messages to thousands of its customers to alert them to the situation on the evening the boil- water order was imposed.

The town is also exploring the idea of a reverse cell phone system, Mr. Dutton said, which allows a message to be transmitted from a local cell phone tower to everyone in the coverage area.

Although these ideas may take some time, the town is already taking immediate steps to better communicate with the public during an emergency. The newly revamped town Web site (oakbluffsma.gov) now allows people to sign up for e-mail notifications. The town is also creating banners with general warnings that can be hung over Circuit avenue or other major roads during a crisis, he said.

“The solution has two components: what we can do in the short-term and what we can do over the long-term. Some things, like signs and banners, we can do simply. Other ideas will take some time,” Mr. Dutton said.

At the same time efforts are underway to craft a plan for an Islandwide response in a future water emergency.

Frank Dunkl, co-owner of Chilmark Spring Water, which provided bottled water to Oak Bluffs throughout the crisis last week, said he is working on a county-wide plan that establishes specific sources of drinking water during an emergency. The plan would use several water trucks equipped with filtration systems and other special equipment to transport water to sites like the Martha’s Vineyard Hospital or Island schools.

Mr. Dunkl said he presented the plan at a recent meeting of the Massachusetts Waterworks Association, a nonprofit organization of private and municipal water professionals. He said the plan is in the early stages and would require towns to work together to provide water to the people during a crisis.

“It’s something that municipal water officials don’t really deal with . . . they aren’t accustomed to dealing with regional emergency preparedness plans. It is something that an independent water supplier may be better equipped for. If there is some way we could help, we would be happy to do it,” Mr. Dunkl said.

Mr. deBettencourt said he liked the idea.

“If we can be better prepared by getting together with the Island towns, then I am for it,” he said. “A lot of times people here are opposed to regionalization — for whatever reason. But I think a regional plan for providing water [during an emergency] could really work.”