BARELY A day went by in Maryland’s gubernatorial campaign when Republican Larry Hogan, now the state’s governor-elect, didn’t attack what he disdainfully called the “rain tax” — a levy on property owners and businesses designed to combat storm water run-off, which washes pollutants into the Chesapeake Bay. The “rain tax,” Mr. Hogan insisted, was a “ludicrous” instance of Democrats’ taxing zeal.

On the rare occasion when Mr. Hogan was compelled to go beyond sloganeering and address the issue itself, things got stickier for him. Sure, he said in an October debate, storm water run-off is “an important problem; we obviously need to work with state and county governments to implement the federal requirement” to mitigate its damage to the bay.

But how would Mr. Hogan pay for such a program in lieu of the “rain tax”? He didn’t really say — except to suggest that maybe counties could somehow conjure the funds on their own without imposing a tax.

That formulation was in keeping with much of Mr. Hogan’s campaign, which relied on the premise that the state could painlessly cut taxes and spending. Now he faces a test. Mr. Hogan correctly pointed out that Gov. Martin O’Malley’s administration raided more than $1 billion in environmental funds and redirected them for other budgetary priorities — much as many states shuffled dollars to cover shortfalls during and after the recession. Had that money been spent as originally intended, no “rain tax” would have been necessary, he said.

In other words, in Mr. Hogan’s view, the O’Malley administration actually short-changed the environment and the Chesapeake Bay. If that’s the case, how does Mr. Hogan propose to rectify the damage while fulfilling his promise to slash spending?

When pressed, Mr. Hogan pointed the finger for much of the bay’s pollution at the Conowingo Dam, in northern Maryland near the Pennsylvania border, from which sediment washes down the Susquehanna River after heavy rains. That’s a convenient way of shifting blame upstream to Pennsylvania and New York, thereby absolving Maryland of its obligation to tackle pollutants washing off its own fields, driveways and roofs.

It’s also a fallacy. Most environmentalists regard the Conowingo’s sediment build-up as a minor source of the bay’s problems. As Col. J. Richard Jordan III of the Army Corps of Engineers Baltimore District told a U.S. Senate hearing this year, it would cost up to $3 billion to dredge just 15 percent of the sediment at the Conowingo Dam and would yield “very little bang for the buck downstream.”

Mr. Hogan has had virtually nothing to say about Maryland’s so-called “flush tax,” assessed on homeowners using septic systems, which is being used to upgrade dozens of sewage treatment plants whose discharge affects the Chesapeake. Of course, the “flush tax” was signed by Maryland’s last Republican governor, Robert L. Ehrlich, in whose administration Mr. Hogan served.

The point is that cleaning up the bay will not happen automatically or free of charge; one way or another, Maryland will have to foot its share of the bill. And sooner or later, Mr. Hogan will have to stop mucking around in Conowingo Dam sediment and level with Marylanders.