Saying she feels “it is imperative” to run again, Mayor Jeannette McCarthy announced Monday she is running for a fourth term, setting up a battle against a longtime local legislator.

Saying she feels “it is imperative” to run again, Mayor Jeannette McCarthy announced Monday she is running for a fourth term, setting up a battle against a longtime local legislator.

“Over the past few weeks, many people have asked me if I am running for mayor,” McCarthy said in a letter to the editor. “The answer is yes. I look forward to the campaign next year in 2015.”

McCarthy announced last year that she would not run for re-election in 2015 to take care of family but later said she was reconsidering the decision.

State Rep. Tom Stanley said Monday he will also be a candidate for mayor.

“Waltham needs vision, not reaction. I cannot sit by while our city drifts waiting for the next culvert to collapse,” Stanley said in a statement. “Our city can’t take 16 straight years of excessive administrative turnover, infrastructure neglect, poor public safety decisions, overcrowded schools, no capital planning, unfriendly business climate and mismanaged public projects.”

McCarthy said in a statement she believes it is not in the best interest of the city to “take commercial property off the commercial tax rolls and build huge residential complexes like 36 River St., which are allowed by City Council special permits and over which the mayor has no authority.

“It is only going to get worse if Waltham elects a mayor who puts developers and special interests ahead of the residents of Waltham,” McCarthy continued. “I don’t, I never have, and never will. In the projects not involving City Council special permits, I ensured that the best interests of the city were protected. I believe in protecting our neighborhoods and in balanced development – not over-development.”

Stanley, who represents the 9th Middlesex District, won re-election to an eighth consecutive term in the State House in November. He has also served as a city councilor-at-large since 2006, and before that from 1998 to 2004.

“The city of Waltham deserves real 21st century leadership,” Stanley said. “We need a leader who will restore basic order and fiscal discipline and lead our city to ensure Waltham citizens are getting the most of their hard earned tax dollars.”

Specifically, in the past year, Stanley has often raised concerns with the city’s inflow and infiltration (I&I).

“Ten years into DEP's Administrative Consent Order, Waltham's I&I problem is only getting worse,” Stanley said, referring to the requirement that anyone altering property in any way that contributes additional wastewater to the sewer system to either pay a calculated fee or be responsible for mitigating the system, depending on the size of the project. “The mayor's management of I&I poses a triple threat to our public health, natural environment and economic stability.

Stanley said he has a fundraiser scheduled for Dec. 11 at Shoppers Café but will have a formal kickoff for his run in 2015.

McCarthy previously said in 2003, when she was running the first time, that she wouldn’t run for more than two terms. However, in January 2011 she changed her mind and defeated Andrew Wirth to win a third term.

The mayor said she would like an opportunity to finish the many ongoing neighborhood and city projects.

“I look forward to discussing more issues as the campaign unfolds,” McCarthy said.