In June, Charles Kunz stayed at the Westin Atlanta Airport and found “the largest cockroach I’ve ever seen” on his bed the next morning. The lawyer from Durham, N.C., a Titanium member of Marriott’s Bonvoy loyalty program, said the insect “was the size of my pinkie. I live in the South and I’m no stranger to bugs.”

In July, Jeff Coons and his wife spent three nights at the Sheraton Panama City Beach Golf & Spa Resort in Florida. The Smyrna, Ga.-based airline product development executive and Bonvoy Lifetime Platinum member found mask usage “seemingly optional” among hotel staff, and only one hand sanitizer dispenser could be found anywhere. The toilet seat assembly in his bathroom was broken, and there was an oversized Lego block beneath a guest room chair.

Major hotel companies have been promoting new cleaning initiatives since the spring as a way to regain the confidence of the traveling public in the wake of the coronavirus pandemic. But some guests at hotels in the United States — including their most valuable guests, loyalty program members — say they are not living up to their promises.

Addressing the experiences described by Mr. Coons and Mr. Kunz, a spokesman for Marriott, whose brands include Sheraton and Westin, said the company “has had a longstanding reputation for high standards of hotel cleanliness.” The spokesman, John Wolf, said these standards have been enhanced multiple times since the pandemic began, adding that in the “rare” case a hotel does not comply with them, Marriott works to “reinforce” them.

Other travelers, after stays at both chain and independent hotels across the country, have gone to TripAdvisor, Facebook and forums like FlyerTalk to report dissatisfaction with enforcement of cleanliness and mask-wearing standards. Chain hotels receiving complaints included Embassy Suites by Hilton Myrtle Beach Oceanfront Resort in South Carolina and Marriott’s Gaylord Opryland Resort & Convention Center in Nashville. Among the independent hotels cited recently on TripAdvisor were the Boar’s Head Resort in Charlottesville, Va., and Hawks Cay Resort in Duck Key, Fla.

“I wouldn’t be surprised if this becomes the center of a coronavirus outbreak,” wrote one commenter on TripAdvisor after listing concerns about the cleanliness of the common areas and hotel rooms at the Boar’s Head. (The general manager responded on the site, writing, “I can assure you that the experience you had and may have witnessed is not standard, nor OK, especially now. I can assure you and others that our staff and our property have very strict protocols for the safety of our guests.”

The issue of cleanliness aside, the pandemic has wreaked havoc with all sectors of the travel industry. According to a report issued last week by the U.S. Travel Association, a trade group, the pandemic, since the beginning of March, has resulted in more than $341 billion in cumulative losses for the travel industry in the United States. In a forecast released this month, STR, a lodging research company, and Tourism Economics, a forecasting and analysis firm, predicted “full recovery in U.S. hotel demand and room revenue remains unlikely until 2023 and 2024, respectively.”

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But cleanliness, or the lack thereof, is the primary factor for would-be travelers, according to a study to be released today by the American Hotel and Lodging Association. Surveying around 700 travelers who spent five or more nights in a hotel in 2019, the study aimed to uncover frequent travelers’ sentiments about enhanced cleaning standards.

When presented with eight factors that could determine their next hotel stay, the highest percentage of respondents — 34 percent — reported that cleanliness was the number one factor when choosing a hotel. Other factors included safety, price and location.

Henry Harteveldt, the founder of Atmosphere Research Group, a San Francisco-based travel market research firm, also conducted a survey of 2,500 business and leisure travelers in the United States last month. Three-quarters of respondents said they were somewhat or very concerned about catching Covid-19. Of the approximately 1,060 respondents who had stayed at least once in a hotel in the previous year, over 80 percent said it was important that hotels exceed guidelines for cleaning guest rooms issued by the World Health Organization and Centers for Disease Control and Prevention. The C.D.C. guidelines include, among other measures, the frequent use of E.P.A.-approved disinfectants on “surfaces and objects touched by multiple people,” as well as practicing social distancing and wearing masks.

If hotel owners fail to maintain cleanliness standards, Mr. Harteveldt said, “guests may be fearful about what else could go wrong. This could affect their willingness to return to the hotel and their brand loyalty to the hotel group.”

Although hotel companies, including Marriott and others, have instituted these new cleanliness standards, in many instances they do not own or operate the hotels bearing their brand names. According to STR, 61 percent of the 56,300 hotels in the United States today are branded, while 39 percent are independent. Most branded hotels are independently owned and operated by third parties, who are responsible for maintaining a brand’s cleanliness standards.

“Just because you walk into a hotel that has a brand name associated with it, that doesn’t mean the brand has any direct management involvement with that property,” said Mr. Harteveldt.

Not surprisingly, cleanliness issues also pose problems for some hotel housekeepers.

Lydia Hernandez, who has worked as a housekeeper for 15 years at the Hilton Philadelphia at Penn’s Landing, is a member of Unite Here, a hospitality workers’ union in Canada and the United States. When the pandemic began, she only worked one day a week; more recently, she has been working five days a week, 8.5 hours each day. Ms. Hernandez said the hotel currently has between eight and 10 housekeepers working full-time; before the pandemic, she said there were 35.

Her greatest concern now is the number of guest rooms she is assigned to clean daily. Before the pandemic, she cleaned all guest rooms every day, a process she said took half an hour per room. Now she only cleans a guest room when a guest checks out and must follow Hilton’s new cleanliness standards. These include deep-cleaning 10 high-touch areas, decluttering paper amenities and placing a seal on the door of the guest room to indicate it has not been entered since it was cleaned.

Many guests today, she said, are “messier. They leave rooms to the point where it’s a disaster. They drink, eat chips, throw these all over the floor, in the bathroom, bathtub. It’s really bad.”

She frequently cannot complete cleaning of the 14 guest rooms she is assigned daily because of the length of time each requires. It normally takes her between 40 to 60 minutes to clean a guest room today, more than an hour if it is especially dirty.

The Hilton Philadelphia at Penn’s Landing is managed by Pyramid Hotel Group and owned by a local developer Daniel J. Keating, III. Alan Cagle, the general manager, called the hotel’s commitment to the safety of team members and guests “second to none,” and noted that the hotel “has maintained an open line of communication with housekeepers regarding their workload during the pandemic.” He also said the hotel’s standard practice now to clean guest rooms only when a guest checks out limits “potential exposure and risk for our essential employees.”

Daily room cleaning was the norm before the pandemic; for sustainability and cost-cutting reasons, some brands permitted guests to opt out. The W.H.O. currently recommends suspending these opt-out programs, a step some hotel companies have taken in the wake of the pandemic.

The frequency of room cleaning is a topic of much debate in the industry: Last month the city of San Francisco’s board of supervisors passed a “healthy buildings” ordinance that requires daily hotel room cleaning. Local hotel groups and AHLA are suing, claiming the ordinance would “create hardship for an industry that is already suffering.”

In the new AHLA study, almost 90 percent of respondents said limiting in-room housekeeping to “by request only” would increase their comfort level, and almost 60 percent did not want daily housekeeping.

If hotel owners neglect new cleanliness standards, Mr. Harteveldt warned this could come back to haunt them in the age of social media.

“People can and do share all aspects of travel. To post images of dirty or inadequately cleaned rooms that others may see, with the risk that the images go viral, will create a much bigger problem for the hotel owner and brand in the long run than the cost of properly cleaning the rooms,” he said.