Leon said the shuttering of the facility was a surprise to city officials and he only learned about its financial situation after reading media reports.
Citing declining membership and sluggish financials, the West End YMCA announced in early January that it would shut the doors of its Ontario site.
"I am not happy with the YMCA and the way the city of Ontario was treated," Leon said.
"They sprung it on us, shocked us with the news that they were closing."
Leon, who is running for the state Senate 32nd District seat, has asked city staffers to prepare a study regarding the future use of the now-defunct facility.
YMCA officials have said the facility was operating with a $140,000 deficit and had lost more than 150 members in the past three years.
"It was closed because the declining age and the condition of the building and the expenses of keeping the building," said Debra Anderson, president/CEO of the West End YMCA.
The West End YMCA also oversees Y programs at branches in Chino, Upland and Rancho Cucamonga.
Even though the building has closed, the YMCA continues to run programs outside of the building such as child care and senior transportation services.
Two years ago, the Ontario Y at North Laurel Avenue and West C Street ran a $52,000 deficit. Last year, the shortfall was $140,000.
But Leon faults those deficiencies on changes that occurred within the organization in 2010. That year, the YMCA decided to reorganize its structure and eliminated executive positions in Ontario and Rancho Cucamonga. The change in administration resulted in the dismantling of the Y's entire Board of Directors.
Since then, Leon said there has been a lack of support from the new administration for the Ontario facility, specifically a lack of fundraising. The mayor said the Ontario facility started to really struggle when the Chino branch took over control of the facility.
"If you (manage) it from out of town it does not survive," he said.
"This city did not let that facility down, the YMCA let that facility down."
In years past, the board's fundraising efforts led to "hundreds of thousands of dollars," being poured into the upkeep of the building, Leon said.
For example, the board was instrumental in several fundraising initiatives such as "Fiesta de Comida," which was held at the Ontario Convention Center.
But that all ended with the dissolution of the board, he said.
Adam Ackerman, president of Florida-based iMember, which helps YMCAs nationwide with membership campaigns, said he also was frustrated with the closure of the YMCA in Ontario.
In the past year, Ackerman said he made numerous attempts to reach the West End YMCA officials, adding that his company could have easily helped the Ontario facility pull out of its financial mess.
"We helped three YMCAs keep their doors open," he said.
YMCA branches contract his company to help them conduct several membership drives.
Ackerman said his company, which has a call center in Florida, reaches out to residents in a YMCA's service area and invites them to take a tour of the building.
At the building, Ackerman has about half a dozen of his staff provide tours of the facility.
In most cases, he said he has a 40 percent to 45 percent success rate in turning those visitors into members of the branch.
"Last year, we helped 11 YMCAs. It's sad to see stuff like this happen ... we definitely could have helped. That $140,000 would have been a breeze," he said.
For example, Ackerman said his company is currently working with a branch in Warren County, Penn., and has already generated more than 300 new memberships and raised $109,000.
Ackerman's company is not affiliated with YMCA of the USA, the national resource office for all the associations in the United States, but it receives email alerts about all the branches throughout the country. The company then contacts those that are in financial distress.
Ackerman would not disclose what he charges the branches, but said they do not have to pay anything up front and that the locations "make more than us."
When asked why Anderson had not contacted Ackerman, she said "I have no comment to an outside company."
Anderson said the YMCA is moving forward with putting the building up for sale and working on appraisal costs for the sale. She has heard from other nonprofits in the community that have expressed interest in the facility.
Reiterating comments she made since the announcement of the closure, Anderson said the 70-year building had been financially strapped for past 20 years.
There were many attempts to keep the membership up and evaluate its costs, Anderson said.
"It was a decision we felt we needed to make. This is a long-term problem," she said.
"This has been a struggle in this branch for at least some period of time. Because of the age of the building and expense, we really felt we had no other choice than to close this building."
Leon said he would like to study what it would take to take over the facility, and his main concern is there is no other facility for young people in the downtown.
Reach Liset via email, call her at 909-483-8556, or find her on Twitter @DBOntarioNow.