For just under $100 per year they will insure your water service and sewer lines.

Just this evening I got a call that a water line froze and broke.

That would add $700 back into your monthly cash flow and turn it from a negative cash flowing property (-$257 per month, per your analysis), to about $450 per month in POSITIVE cash flow.Also, water & sewer and insurance estimates seem a bit low, but that could just be the area of this property as compared to my area. 

For example, you can get the tenants to mow the lawn - but most tenants will not drag hoses around to water the lawn.  

@Ryan Cotic insurance and water seem a little low, but otherwise it seems correct.

The flow of water is noticeably slower.

Several months into the lease, there was a water leak in the basement and the carpet in the basement had to be replaced.

For a family that uses lots of water it can easily be $1,000/year. 

The sales paperwork said the property had a source of water that met the city drinking water quality standards.

Go to Redfin.com and select the zip code then go to "More Filters" and put in your criteria.