With Mayor-elect Michael Nutter taking direct aim at Philadelphia's pay-to-play political culture, the city's independent Board of Ethics this week gave him yet another big helping hand.

In a ruling issued Tuesday, the Ethics Board said that City Charter limits on political activity applied to appointees at numerous city boards and commissions.

This follows the ethics board's strong ruling in October that curtailed politicking by members of the influential Zoning Board of Adjustment, as well as several other city panels.

All told, the political activity restrictions now apply to more than two-dozen boards and commissions - potentially impacting dozens and dozens of mayoral appointees, many of whom serve without compensation.

The Ethics Board's moves are the regulatory equivalent of trying to change what's in the city's drinking water. That is, it's about cleansing the wellspring of a political climate where connections and insider dealings too often undermine the public's trust.

Just as the charter founders intended, the ethics rulings should limit political motives of appointees who help carry out the people's business. That's important for panels that deal with critical matters such as Civil Service, pensions, planning, parks, prisons, the Philadelphia Gas Works, historic preservation, and the like.

In addition to Ethics Board members themselves, appointees to other city agencies who fall under the rules cannot be political party leaders or even elected committeemen. They can't work for candidates or even display lawn signs, much less raise funds and participate in Election Day efforts, the Ethics Board ruled.

Inevitably, that will alter the pool from which Nutter makes his appointments. He'll probably have to cast a wider net. And, yes, the limits could prevent some civic-minded but politically active people from serving the city. But the Ethics Board reasonably and properly provides for appeals of the limits in individual cases.

The bottom line is that these political-activity limits could yield candidates less likely to bring an agenda to their roles. Along with Nutter's strong appointments of two top ethics aides, the Ethics Board ruling could help stem the cronyism typically in play in City Hall appointments.