(GERMANTOWN, Tenn.) -- A third section of Germantown, Tennessee, was allowed to resume drinking and using tap water Thursday, however, others remain under restrictions that have now been in effect for a week after it was discovered the water supply was contaminated with diesel fuel.
The nightmare began for the city, a suburb of Memphis, after residents began reporting a strong odor to their tap water on July 20. An investigation revealed that a generator being used to power the Southern Avenue water treatment facility -- due to a power outage -- was leaking diesel fuel into an underground reservoir.
Residents whose restriction was lifted Thursday morning have been allowed to begin system flushing and resume consumption and usage of water.
The Germantown Fire Department and other emergency management agencies responded to the scene last week and the leak was stopped. The Tennessee Department of Environment and Conservation was also called to the scene to ensure that the emergency response met state standards.
Residents have been told to only use tap water for toilet flushing. The city also said that boiling water does not make it safe for use.
"The fuel, approximately 100 gallons of diesel, contaminated approximately 4.2 million gallons of water being held on the site," according to the city.
City officials said the next phase will be announced once it can be determined that the system is maintaining adequate pressure for firefighting operations, according to the city.
The water was treated last Friday and the reservoirs were refilled by midday. The city then pumped water into the elevated tower to address any residue remaining in the system and samples were sent out for testing, according to the city.
Some of the samples returned with traces of diesel fuel in them so the city used hydrants to flush the system again.
The water restriction was then partially lifted for customers east of Forest Hill-Irene Road to resume using tap water last Sunday at 9 p.m. while most other customers in the city remained under the order pending further testing.
Aside from the leak, additional contamination was found deeper in the soil immediately surrounding a pipe that was carrying clean water from the treatment plant into the underground reservoir, Public Works Director Bo Mills said in a recorded message to city residents on Tuesday.
"There was a breach in this pipe at this location which allowed the diesel fuel in the soil to enter the reservoir. The pipe has been repaired and the contaminated soil is being removed and contained on site and will be properly disposed of as required by regulations," Mills said.
"Good, clean soil has been acquired to backfill and compact the area in the full repair. The generator has been fully inspected multiple times by outside contractors to ensure that there are no issues with the generator," Mills said.
Customers whose tap water restrictions have been lifted are instructed to flush out their interior service lines to remove water that was standing in interior pipes.
Customers who did not detect the smell of diesel should open all faucets, hot and cold, and leave them running for five minutes. They can then resume usage of tap water.
Those who detected odor from their water should open a couple of cold water taps and run for 15 minutes to clear the customer service line from the main and then -- starting with what is nearest to where the water enters the building -- open each cold tap one at a time and run them for five minutes to clean that line. Both steps should then be repeated, running hot water through the taps, according to the city.
Any dishes or clothing washed while the restriction was in place should be rewashed. To flush water heaters, residents should fill a bathtub and drain it twice, according to the city.
"While the entire Germantown water system is fed by both the Southern Avenue and Johnson Road water treatment plants, the decision to partially lift the restriction was based on the knowledge of how water flows through the system and the absence of odor reports taken in the area," the city said in a statement Sunday.
The city said customers will likely see sediment and discoloration in their water due to the extensive hydrant flushing that the system underwent in the last week.
The city urged residents to wait until their area is released before they begin flushing in order to maintain water system pressure.