It may start free, but almost as soon as the rain hits the ground, it begins to cost money. The Baltimore Department of Public Works has to capture that water, protect its purity, process it, ship it to your spigot and send the sewage off for treatment.

The folks in Baltimore who make sure that water reaches the millions of people who rely on it have their hands full, especially when this old city's aging pipes begin to crack, as they have so spectacularly this week.

So maybe this is the perfect time they tried to educate the public about the often invisible work they do. May 3 to 9 is National Drinking Water Week, and the Baltimore DPW had organized a full week of activities designed to showcase the water system that produces what is arguably the tastiest and most reliable - even in drought - municipal water of any big city in the Northeast.

The week kicks off Sunday from 10 to 3 at Loch Raven Reservoir, where you and the kids can learn about where the city's water comes from, and the history of the valleys and the dams and the three reservoirs that now capture and store the city's water. There's also plenty to know about the critical role we all play in making sure the watersheds that feed these reservoirs stay clean - for us and for the wildlife and the fishery that share the land and water with us.

On the 4th, at noon, there will be an event at the Ashburton Water Treatment Plant (3001 Druid Park Drive) that includes dedication of the renovated atrium, and a screening (5:30 p.m. at the Maryland Science Center) of the documentary "Liquid Assets," describing the water and wastewater systems that keep us all healthy and hydrated.

On Friday, May 8, 12:30 to 2:30, the DPW's water and wastewater employees will be honored at an "Employee Appreciation Event at the Haven Street Maintenance Yard, 804 N. Haven St. These are the guys who repair those pipes, getting wet and muddy in sometimes freezing conditions to keep the fluids flowing under the streets.

Finally, on Sunday May 9, from 10 a.m. to 2 p.m., the public is invited to tour the Montebello Water Filtration Plant 1, at 3901 Hillen Road. Learn how our water system operates, and how the mains are repaired, replaced, cleaned and re-lined. 

It's a tough, expensive job, but someone's got to do it. And, of course, someone's also got to pay for it. So when the city asks for a (another) water rate increase (9 percent) later this year, at least you'll know where the money goes. The proposed hike amounts to $74 a year for a typical family of four using 39 units of water each quarter.

The new rates would mean we would pay five cents for a 10-minute shower. The increase would bump Baltimore from the second-cheapest water and sewer rates to fourth, out of seven nearby jurisdictions. The annual costs for a family of four are now the cheapest of seven eastern cities, the city argues. The increase would bump us to second, leap-frogging New York City, but still cheaper than Philadelphia, Washington, Richmond, Boston and Atlanta.

The money is needed, the city argues, in order to rebuild and replace aged water and sewer lines, and to tackle the rising number of main breaks being reported - 5,000 between January 2005 and January 2009 alone. Leaks cost us all 20 percent of all the water the city processes. Work in the queue includes $2.2 billion in capital improvements to the system.