Light aircraft pilot reported a runway excursion following loss of braking capability after landing on an icy runway.

Narrative

I landed on Runway 3. The surface was black ice with braking action nil. I departed the runway off the right edge. The airplane came to an immediate stop upon contact with snowy terrain. Actions prior to the incident including checking NOTAMs for anything regarding runway conditions and texting the Airport Manager for field conditions. There were no NOTAMS and the Airport Manager did not reply. I looked over the runway and saw no snow on the surface and could see all of the black color of the asphalt. I landed normally. The aircraft began slowing with brake application but when I got down to about 10 to 20 kts. I began sliding until the plane came to a stop.The airplane was not damaged and was easily recovered from the grass. After inspection; it was returned to service.What could have prevented this would be a proactive approach to reporting runway conditions. The airport operator could have posted a NOTAM about poor to nil braking action. He observed wet runways at close of business the day before and the temperature was forecasted to be well below freezing. A NOTAM would have been good; or an advisory when contacted directly would been useful. Armed with better information; I could have diverted to an alternate.