Waterloo Mayor Brenda Halloran will not run again for office in the 2014 municipal election.

Halloran was first elected mayor of Waterloo in 2006, and she says although the decision to not seek office again was a difficult one to make, she felt it was time to move on.

"For me a personal goal was to have two terms," Halloran told CBC News. "Being the mayor of Waterloo has been the best job of my life and I've learned so much and I've gotten skills that I never had before. But I've always been one to push myself and to look for new challenges."

Halloran notified staff of her decision in an email Wednesday morning, and added that she will "continue to serve Waterloo in other ways."

The news came as a surprise to many in the region, including her fellow members of city council.

"As I think I told the mayor, she did something that left me in a very unusual position, I was actually speechless," said Ward 6 councillor Jeff Henry.

Next year's municipal election will be held on October 27.

Below is a copy of the letter the mayor sent to staff.

After nearly seven years as Mayor of the City of Waterloo, I have made the most difficult decision to not seek re-election in the 2014 municipal elections.

In 2006, I threw my hat in the Waterloo mayoral race because I believed that City Hall should be the heart of our community and I wanted to break down barriers to create an environment that was open and welcoming to the people of Waterloo. I believe in the importance of people having a voice in decisions that affect them and I will continue to help our citizens have a strong and healthy voice at City Hall.

I have had the privilege of working closely with our residents, our talented staff, our elected officials, students, and countless community and global leaders. I have been blessed to work with all of you. It has not been an easy road, but it has been extremely rewarding and we have seen positive change take place. I am excited to see what we can accomplish, together, in 2014.

I am very proud that Waterloo has become an even more vibrant place to live, work, learn, and play. I have been proud to share our unique and inspirational story on the global stage. I was honoured to accept our 2007 Intelligent Community award on behalf of the city and subsequently act as Chair of the Alumni group of global intelligent communities. We signed a friendship agreement with Chongqing, China and a permanent Waterloo garden has been created at their international garden expo. I have been able to act as a champion for our social agencies and be a strong voice for those who do not have one. We have maintained a strong commitment to fiscal responsibility. We have seen and continue to see significant investment in our community and I am proud of the collaboration that has occurred to make it all happen. I believe that Waterloo is poised to change the world again.

When you have so much pride in something that you have lived day and night, it is hard to leave. I will continue to serve Waterloo in other ways, working to inspire others to act on their beliefs. Our community is full of strong, positive leaders waiting to shape the future of Waterloo and I am happy to hand the baton to the next Mayor who will love Waterloo as much as I do.

It is hard to say goodbye to a role that holds such purpose and meaning. I believe that life is about possibilities. I am excited about 2015 and I look forward to jumping into the next stage of my life. I will take with me many valuable lessons that I have learned throughout my years as the Mayor of Waterloo.

I am humble and grateful for what this community has provided me, and serving as your Mayor has been the greatest privilege and honour. I am and always will be proud to call Waterloo 'home'.

All the best,

Mayor Brenda Halloran