Call it what it is: a tax. And we’re in favor of it, nonetheless.

Butler soon will offer a $20 monthly parking permit for the Center Avenue, Farmers Market and Quarry Street parking lots — along with a warning from Mayor Tom Donaldson that free parking won’t be tolerated in the three lots once the permitting starts.

By the mayor’s own admission, there’s been little enforcement of parking in these locations, which perhaps explains why they’re filled to near capacity most weekdays, ostensibly by drivers who work downtown and want to save a couple of dollars a day on parking.

The city also assumes the lots’ users are downtown employees, which is why the mayor says, “We’re not going to drive anyone out of town doing this. They’re here anyway. There’s no reason these people are parking for free.”

Regular users of these lots will howl about the loss of their free privilege, but it’s a fact the city needs to maintain and cultivate its revenue streams to remain financially viable. Parking is fair game.

At the same time, it’s incumbent on the city to enforce whatever action it takes regarding parking. Two of the three lots being targeted already have meters, but the mayor admits the enforcement of metered parking in recent months has been lax. A portion of the anticipated revenue from parking permits must pay for more aggressive enforcement.

Enforcement is likely to eventually include towing and impounding the cars of violators, according to the mayor, who rightly points out any regulatory changes have to include a willingness to apply penalties for violations. However, the prospect of towing raises questions about the city’s preparedness to back up Donaldson’s threat: are laws and provisions in place for towing and impoundment? And will the violators be on the hook for the added expense before they can reclaim their vehicle?

Such details have to be worked out and adopted as ordinances, and those who work and park downtown need sufficient notice about the changes, before they take effect.

A parking fee is, in essence, a tax. All motorists who take advantage of city parking should pay for the privilege, and it’s well known the city is starved for revenue. Mayor Donaldson deserves support and should be encouraged to continue his pursuit of his parking intitiative.