(CNN) - Former Secretary of Housing and Urban Development Julián Castro got his fourth qualifying poll on Thursday, meaning he has now met both the polling and fundraising thresholds to participate in the third Democratic primary debate in September.

WAUKEE, Iowa (CN) – Democratic presidential candidate Julian Castro put on his hat as former head of the Department of Housing and Urban Development in a visit Friday to an Iowa mobile home park where residents were recently stunned by rent increases by the new out-of-state owners

"And during this campaign, one of the things that I've called for is for us to invest in affordable housing. I bet you that if we went through the debate transcripts of the last 40 or 50 years, Democrat and Republican debates, that we wouldn't see one question that was about housing, even though today, in big cities and small towns, there is an affordability crisis. People are paying 50 percent, 60 percent, 70 percent of their income in rent, right? So what I learned, what I learned from my time at HUD was that we did a lot of great work. We reduced veteran homelessness in the Obama administration by almost half from 2010 to 2016. We did make sure that people could stay in their home. We made fundamental improvements to investing in communities. At the same time, I think we still need to do a lot more. And I look forward to doing that if I'm president." 

DES MOINES, Iowa -- Presidential candidate Julián Castro already made a visit to the Iowa State Fair, but he is continuing to campaign in Iowa.

Tuesday afternoon the former Housing and Urban Development secretary held a town hall meeting on affordable housing. Castro was joined by developers, community leaders and affordable housing advocates to address housing concerns in cities, suburbs and rural communities.

It was the first visit a presidential candidate made to Midwestern County Estates in Waukee, an Iowa mobile home park where residents were recently notified that rents are being raised by nearly 70% in coming months.

Democratic presidential candidate Julián Castro on Friday toured the flood tunnels underneath the Hard Rock Cafe in Las Vegas, accompanied by local organizations working to end homelessness.

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The former Housing and Urban Development secretary walked the city's storm tunnels where hundreds of individuals seek shelter, using his campaign platform to highlight the issue of homelessness in Nevada.

The strength of our nation has always been our capacity to learn from our failures and work together towards a better future. For generations, Indigenous communities have been treated as second-class citizens rather than sovereign tribal nations free to determine their destiny. The federal government has repeatedly failed to honor treaty obligations, respect unique government-to-government relationships, and allowed corporations to exploit sacred land for their own profits.

“Everybody needs a decent place to live,” he said. “We need to make big investments in housing supply throughout our country—from significantly expanding the low-income housing tax credit to boosting things like Community Development Block Grants and HOME funds to boosting the U.S. Department of Agriculture’s investment in rural housing opportunity and finding a better revenue source for things like the National Housing Trust Fund, which is aimed specifically at people categorized as extremely low income. I support all of those things.”