From Milwaukee County Supervisor Shea, via his Facebook page …
The Parks Department reached out to my office today to share the sad news that South Milwaukee’s Grobschmidt Pool suffered a large and destructive water main break overnight. Workers are focusing on assessing damage and repair in the near term. The pool will be closed for the foreseeable future. Please let your friends and neighbors know that we will need to use Sheridan instead for the time being. I’ll share updates as I receive them.
The county tells me it was its service that broke. Nonetheless, it’s a blow to this South Milwaukee institution. I’ll keep you posted.
South Milwaukee Blog 
I saw your email, took a walk to the pool, did not see any work or trucks at the pool. Did city hall have a water problem? Reason I’m asking — is this an excuse to just close the pool early with only 1 week left?
Not at all. It was a break in their water service, not a city main. So no other properties were impacted.
No excuse at all. My daughter is the head lifeguard there. It is a mess. Several feet of water. These employees really count on that summer money, so it is a huge blow to them too.