If you left your car running, the waterpump would just be running anyhow...
Don't think of it as more wear on your waterpump,
think of it as less wear on your engine (and gas card!)
06 330i 6mt Spt- Eibach Springs, BMW Perf Susp, Supersprint Exhaust, BSW Audio
RIP-94 325i 5mt 4d- M3 springs/susp, Z3 wheels, Chipped, Intake, Exhaust= FUN!