really not in hot water

We had some cold times here in Arlington earlier this winter, and we managed to be blessed with hot showers all through those periods; for some reason, however, that blessing has now been removed from us. The weather isn't even that cold anymore--unseasonably warm, even--but we've been having to run the water for like three or four minutes before getting in the shower to give it time to approach bearably warm. And since the heat from the radiators is also just getting started about the time we want to be getting in the shower in the morning, bearably warm just ain't good enough. Too bad I don't know the first thing about water heaters and pipe insulation: I don't even feel like I know enough to call the landlord and ask about the problem! Oh well, spring will be here soon... I hope...