(CNN) -- When it comes to cloudy, rainy days, Portland, Oregon, ranks high among U.S. cities. But even with all that moisture, the tap water for hundreds of thousands in and around this Northwest city isn't safe to drink, authorities say. 
 
 The Portland Water Bureau on Friday urged about 670,000 people in its region to boil water they drink, use to prepare food or make ice, or brush their teeth with after three tests came back positive for E. coli bacteria. 
 
 "Boiling water is an inconvenience, but it's the best way to protect until more information on the extent of contamination is known," water bureau director David Shaff told reporters. 
 
 Customers cleared bottled water off supermarket shelves in the hours after the announcement. Rose Festival CityFair -- an annual festival along Portland's waterfront -- was also affected, with event spokesman Rich Jarvis telling CNN affiliate KOIN all vendors were told to dump any food or drink products that somehow used tap water and start over. 
 
 Jared Brown, from the southwest Portland restaurant Mama Mia Trattoria, told KOIN that his staffers went out to buy 20-gallon jugs of water and bags of ice, while boiling heaping amounts of water for use. What his restaurant is not doing, though, is closing. 
 
 "We have reservations this evening," Brown said, "and I'm not letting them down." 
 
 Online people have responded to the situation -- in some cases with anger, in many others with humor. 
 
 One man accused Portland -- "a city where it rains ⅔ of the year" -- of being "dumb about water" issues. Another blasted officials for it being three days between the first positive test and when officials decided to tell the public. 
 
 Others had less serious takes on the predicament, like one who sarcastically screamed on Twitter about the "#Portland Boil Water Notice Apocalypse 2014! #onlybeerissafe." One man tweeted, "I always thought Portland water tasted like poop. Now I know why." And there was one opportunist who joked (one thinks) he'd sell Two Buck Chuck -- wine that sells for $2 at Trader Joe's -- "for only $200 a bottle." 
 
 In shades of the cult comedy show "Portlandia," one tweet featured a well coiffed boy wearing a crisp denim button-down shirt and a hefty scarf, with his hands in his pockets and his bespectacled eyes staring straight at a camera. It also had this caption: "This is a Portland hipster child. For just .30/day, you can help provide him with clean drinking water." 
 
 Such light jabs aside, the ordeal is proving to be a major inconvenience to many. 
 
 The first sign of trouble came Wednesday, when a "routine sample" taken the previous day tested positive for E. coli. Fresh tests in and around that area came back clean, as did most other tests. But there were also two additional samples that did not. 
 
 "Independently, we had all of these things happen. Normally, ... there would be nothing further," Shaff said. "The state, though, has said with these three incidents right after the other, we're going to require you to (act)." 
 
 The boil water advisory affects customers of the Portland Water Bureau and water districts for Burlington, the city of Gresham (north of Interstate 84), Lake Grove, Lorna Portland Water, Palatine Hill, Rockwood, Tigard Water Service Area (including Durham, King City and Bull Mountain), Valley View and West Slope. 
 
 All tap water in those areas should be boiled at a full rolling boil for at least one minute, officials said. Ice or beverages prepared with tap water on or after May 20 should be discarded, officials said. 
 
 Dr. Paul Lewis, the interim Multnomah County Health Officer, urged people to follow the recommendations. At the same time, he downplayed the threat to the community, saying he didn't "think there will be any detectable increase in diarrheal illness." 
 
 "We think, overall, this is a very cautious approach that we're taking," Lewis said. "We think that the risk to the public is very low." 
 
 This isn't the first time residents of northern Oregon have been asked to take such precautions. The Portland Water Bureau issued a boil water alert to 135,000 area households in 2012 and to 50,000 residents in 2009, both because of E. coli contamination, the Portland Oregonian reported. 
 
 Both those restrictions were lifted the next day. 
 
 Will the current advisory be similarly short-lived? Portland residents won't find out the next steps until Saturday morning, when the next set of results are in. 
 
 What to know about E. coli 
 
 E. coli symptoms, prevention and treatment 
 
 CNN's Michael Martinez contributed to this report. ||||| Lucy Ohlsen / OPB 
 
 About 670,000 people are affected by a boil water advisory in Portland, officials said Friday, and it will remain in effect until further notice. 
 
 All Portland Water Bureau customers and those in the affected areas are being advised to boil all tap water used for drinking, food preparation, tooth brushing and ice for at least one minute. Ice or any beverages prepared with un-boiled tap water on or after May 20 should be discarded. 
 
 “We know and regret that this is an inconvenience,” City Commissioner Nick Fish said, but added that public health must be the priority. Fish and other city officials directed concerned residents to a water bureau website, but the site was inaccessible for much of the morning, perhaps due to high Web traffic. City officials said they were working on shoring up the site, which allows residents to look up their address and see if they are affected by the order. 
 
 New test results are due in on Saturday morning and a press conference is planned. “In a perfect world,” Fish said, the notice would be lifted then, but officials will need to wait for the results of additional water quality testing to make any determinations. 
 
 “We may never discover the actual cause of the contamination,” said David Shaff, Portland Water Bureau administrator, though officials believe that it is either human or animal fecal matter. 
 
 Dr. Paul Lewis, the health officer for Multnomah and Clackamas Counties, told reporters he doesn’t expect a detectable increase in diarrheal illness from the incident. He added that there is no evidence to suggest that the E.coli presence is linked to national reports of E.coli found in sprouts, which has sickened a handful of people in Idaho and Washington or reports of E.coli found in hamburgers that sparked a recall of 2 million pounds of beef in a dozen states. 
 
 Students and staff at school districts around the region have been told to avoid drinking fountains and nutrition officials said they would take steps to insure food safety during lunch periods. 
 
 Water fountains and splash pads are being shut down in parks around the city. 
 
 Think Out Loud broadcast the press conference live at noon Friday. 
 
 
 
 View Portland Water Bureau Boil Water Notice 5/23/2014 in a larger map 
 
 The Portland Water Bureau has released this Google map of affected areas. 
 
 Both reservoirs have been taken offline. 
 
 Results from three separate samples, taken May 20, 21 and 22 and returned to the Water Bureau May 21, 22 and 23, confirmed the presence of coliform and E. coli in routine drinking water samples. 
 
 The water samples that tested positive for bacteria were collected at the outlets of Mt. Tabor Reservoirs 1 and 5, and at the SE 2nd Avenue and Salmon Street water sampling station. After reviewing the results, state officials ordered the boil advisory Friday morning. 
 
 A boil order was issued in summer of 2012, but it affected just areas of Portland west of the Willamette. City officials confirmed that this is the largest such order in Portland’s history. ||||| Portland boil-water alert: Live updates. 
 
 UPDATED: This post was updated with additional information 
 
 The Portland Water Bureau issued a city-wide boil notice on Friday morning after water staffers detected E. coli in three separate tests during the past three days. 
 
 The Oregon Health Authority required the city-wide notice, which also applies to Portland's whole-sale customers that also receive water from the Bull Run Watershed. 
 
 Routine inspections at two of the city's Mt. Tabor reservoirs produced the three positive E. coli tests. City employees performed the tests, according to Jaymee Cuti, bureau spokesperson. 
 
 State officials said the tests showed signs of fecal matter. 
 
 The boil notice applies to 670,000 customers, according to Cuti. Portland supplies drinking water to 935,000 customers in the metro region. 
 
 City officials hosted an emergency press conference at noon. 
 
 "While we believe at this time that the potential health risk is relatively small, we take any contamination seriously and are taking every precaution to protect public health," said Portland Water Bureau Administrator David Shaff in the release. 
 
 The Oregonian will be there and this story will continue to be updated. 
 
 Cuti said the boil notice will be in effect until the city produces "a clean sample." Cuti said she has no idea when that might be. 
 
 Here's the full release from the city: 
 
 The State of Oregon Health Authority's Drinking Water Program has required the City of Portland to issue a Boil Water Notice for all Portland Water Bureau customers and some regional water providers. 
 
 Until further notice, all Portland Water Bureau customers and those in the affected areas should boil all tap water used for drinking, food preparation, tooth brushing and ice for at least one minute. Ice or any beverages prepared with un-boiled tap water on or after May 20 should be discarded. Detailed maps, fact sheets and additional information can be found on the Water Bureau's website at www.portlandoregon.gov/water/boilwaternotice or by calling Customer Service at 503-823-7770. 
 
 In three separate incidents from May 20 to May 23, repeat water samples confirmed the presence of total coliform and E. coli in routine drinking water samples. The water samples that tested positive for bacteria were collected at the outlets of Mt. Tabor Reservoirs 1 and 5, and at the SE 2nd Avenue and Salmon Street water sampling station. Both reservoirs have been taken offline. 
 
 A press conference will be held at noon today at the City of Portland Emergency Coordination Center, 9911 SE Bush Street in Portland. 
 
 All Portland Water Bureau customers are affected. Also affected are customers of the following water providers: 
 
 Burlington Water District 
 
 City of Gresham (North of I-84) 
 
 Lake Grove Water District 
 
 Lorna Portland Water 
 
 Palatine Hill Water District 
 
 Rockwood Water District 
 
 Tigard Water Service Area (including Durham, King City and Bull Mountain) 
 
 Valley View Water District 
 
 West Slope Water District 
 
 "While we believe at this time that the potential health risk is relatively small, we take any contamination seriously and are taking every precaution to protect public health," said Portland Water Bureau Administrator David Shaff. 
 
 Consuming boiled and bottled water will ensure public health protection until the Water Bureau can determine that the water system is clean of contamination through surveillance sampling. Customers will be notified when they no longer have to boil their water. The Portland Water Bureau is working with the Multnomah County Health Department to provide health-related information to the public. 
 
 "The chance of any health problems related to this water test result is low. If any problems occur, we would expect diarrhea," said Dr. Paul Lewis, Interim Tri-County Health Officer. "We monitor cases of bacterial diarrhea and will be aware of any increase following this event." 
 
 The Portland Water Bureau collects approximately 240 routine bacterial samples per month throughout the system. The test to determine the presence of bacteria takes about 18 hours. It is not unusual for one of these samples to test positive for bacteria. Samples to confirm possible contamination are collected immediately after an initial detection of the presence of bacteria in drinking water. Once the detection has been confirmed, public health officials recommend that the public boil all tap water before consuming. 
 
 Contamination can occur when there is a loss of water pressure, a pipe breaks, or conditions that expose drinking water to outside elements. The Portland Water Bureau is performing a full investigation to identify the cause of the contamination. However, it is not always possible to make an exact determination. 
 
 Customers can visit www.portlandoregon.gov/water/boilwaternoticeto determine if their home or business is in the Boil Water Notice area. The Boil Water Notice, fact sheets and contact information are provided on this same website. For more information, affected customers should contact the Portland Water Bureau Customer Service at 503-823-7770. 
 
 Do not call 9-1-1 unless you have an emergency. Follow updates on Twitter at #PDXBOIL.
– Residents of Portland got some more not-so-great news today about their water: The city wants everybody to boil it for the time being because three separate E. coli tests came up positive, reports the Oregonian. The advisory affects 670,000 people, though a city official called the risk "relatively small," reports CNN. New test results will be in tomorrow morning, and it's possible the advisory could be lifted then, reports OPB. The city's water supply made national headlines earlier this month after a teenager got caught peeing in a reservoir (though he denies it).