Some US pools remained open and packed for July Fourth while others closed due to high COVID-19 cases

People swim in the water at Coney Island as the city moves into Phase 2 of re-opening following restrictions imposed to curb the coronavirus pandemic on July 4, 2020 in New York City.

Beaches across the country were closed this Fourth of July weekend, but some pools and aquatic areas in the U.S. remained open, despite a recent uptick in coronavirus cases.

 "We will see an increase in cases if people were not following social distancing, mask-wearing, and hand-washing guidelines over the 4th of July weekend," Keri Althoff, epidemiologist at John Hopkins Bloomberg School of Public Health, said. "It doesn’t matter if these principles were being violated at a pool or elsewhere. It is not recommended to wear a mask while swimming, but when not swimming, masks should be worn if you are unable to keep at least 6 feet of distance from others."

Here is a look at where pools, lakes, beaches and water attractions remained open and closed throughout the country:

Pools and water destinations that remained open

In Las Vegas, many pools at resorts along the Vegas strip remain open to guests. Phase two of Nevada’s reopening plan — which was recently extended — allows pools to operate. As of July 6, there are 735 known COVID-19 cases in Las Vegas's Clark County.

MGM Resorts, which owns major hotels in Las Vegas, tweeted on Friday, July 3 that they are “dedicated to ensuring you're able to enjoy Vegas, safely. We’ve implemented a variety of measures at our resorts nationwide to help protect your health and safety.”

Wynn properties limited their pool capacity to 50% to allow for social distancing measures. “All high-touch surfaces are disinfected every hour and lounge chairs are disinfected after each guest. Face coverings are required when guests are not in the water, sitting at a lounge chair, or walking to/from the water to a pool lounge chair,” the resort said.

In Michigan, Diamond Lake was packed along its shores over the 4th of July weekend. Noah's Ark Waterpark in Wisconsin Dells, Wis. also showed heavy crowds over the holiday weekend.

In New York, Governor Andrew Cuomo announced outdoor pools across the state would open for swimming for the holiday weekend. “Pool-goers are reminded to practice social distancing, respect the rules, and do their part to keep the pool area safe for everyone,” the public safety announcement read. "As we are getting ready to celebrate the Fourth of July, we must remember all the sacrifices New Yorkers have made to flatten the curve of the pandemic and be cautious in everything we do," Gov. Cuomo said.

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Pools and water destinations that were closed

But in other parts of the country, beaches and pools were closed following upticks in COVID-19 cases.

Miami closed its beaches Friday through Tuesday. Mayor Carlos Gimenez signed an order Tuesday requiring all pools at hotels to close from 8 p.m. each night until 6 a.m. the following morning.

In Arizona, Gov. Doug Ducey shut down pools again after a resurgence of new cases developed in the state. Gov. Ducey’s order went into effect for at least 30 days.

What are the COVID-19 health guidelines for pools?

According to the Centers for Disease Control and Prevention (CDC), there is currently no evidence that the virus can spread through the water in pools. Being outdoors also can reduce the likelihood of transmission, and practicing social distancing can also help to keep people safe.

"The rise in cases is threatening healthcare systems in some states and likely slowing the economic recovery," Althoff said. "We all need to be maintaining social distance, wearing masks, washing hands, and engaging in low-risk activities in order to avoid more hardship and deaths."