Does this change meter sizing or water bills?

Maybe, but not always. Studies have shown that typical ⅝-inch domestic meters can meet the required flows of an NFPA 13D system, even where those flows exceed the meter's maximum rated flow. The Residential Fire Sprinklers–Water Usage and Water Meter Performance Study, conducted in 2011 by NFPA's Fire Protection Research Foundation, found that domestic meters can sustain flows above their rated maximum without damage, particularly because the high flow rates occur infrequently and for short durations. Some utilities assign sprinklered homes a larger meter, ranging from ¾-inch to 2-inch, with most at ¾-inch or 1-inch. Metering technology is also improving; some utilities are moving to solid-state digital meters that can serve a fire sprinkler system at sizes as small as ⅝-inch or ¾-inch. Because many utilities set fixed charges by meter size, a larger meter can raise the monthly cost. Some utilities have solved this by creating a separate rate class for sprinklered homes, as Philadelphia did in 2011.