HOUSTON, Texas (KTRK) -- According to Houston's health authority Dr. David Persse, the U.K. variant is being found "in large amounts" and is spreading throughout the city fast.
He said on Feb. 8, the U.K. variant was found in 21 of the city's 39 wastewater treatment plants. Fourteen days later, on Feb. 22, he said the variant was found in 31 out of 39 treatment plants.
"19% of all the virus that has been tested in the wastewater across the city has the genome that's consistent with the U.K. variant," said Persse. "That does not mean that 19% of the people in Houston are infected with the U.K. variant ... it does not mean that. We know that there is a fairly large amount of the U.K. variant in our community and it is spreading."
As of Monday afternoon, Persse said the wastewater is being tested for other COVID-19 variants, such as the Brazilian and South African variants.
However, the measurements have not been concluded, therefore new data was not available to report, Persse said.
WATCH: Variants in Houston wastewater: Should we be alarmed?
"We are concerned about people dropping their guard and not wearing their masks and gathering in ways in which they wouldn't," he said. "Remember, the U.K. variant is the one that spreads much more easily. Those viruses are in the community so, the race is on to get as many people vaccinated as possible before the U.K. variant is able to take over and cause us to have another surge"
As of Monday afternoon, Houston Mayor Sylvester Turner said the positivity rate across the city is now 13.1%, which has increased since last week.
The city's health department said this is the second week in a row in which the positivity rate has seen a slight uptick.
In addition, the city has reported 318 new coronavirus cases, making the total case count 175,150. The death toll now stands at 2,018.
"We continue to make progress [and] getting people vaccinated, but we are nowhere near landing herd immunity," said Turner.
Texas is two days away from being "100%" open but Turner offered what he described as "a glimmer of hope."
During his briefing on Monday, Turner said the owner of Concrete Cowboy, a popular Houston bar on Washington Avenue, wrote Turner an email to advise him that a planned "mask-off" party has been canceled.
"It was never our intention to host a party where we encourage patrons to not wear a mask," stated the email, which was read aloud by Turner during his briefing. "I'm a business owner of multiple venues in the Washington corridor and public safety is our top concern."
READ MORE: Houston Mayor Sylvester Turner wants planned 'maskless parties' at bars to be canceled
The Texas' mask mandate lift and the several "mask-off parties" has caused concerns of other similar events from other states coming to Texas. Turner said promoters in states that are not allowed to operate at 100% and forced to wear a mask, are promoting bringing those events to cities like Houston, Dallas and Austin.
Turner said Concrete Cowboy will not be open Wednesday night.
"This is not the time to drop our masks or drop our guard in the fight against the pandemic," said Turner.