Don't make rules you can't enforce.

That bit of basic wisdom, which could apply to parents, teachers, coaches, elected leaders or anybody in authority, seems to have been forgotten in some cases in Gloucester.

In 2005, the city mandated that the owners of buildings supported by pilings and piers have them inspected at least once every three years. There was compelling evidence that such a rule was necessary - during a snowstorm that February, the pilings supporting a wing of the Cape Ann Marina Resort collapsed several feet, trapping 20 guests who had to be rescued by firefighters.

But it appears that, while reacting quickly to what might have been a disaster, city officials didn't think through what it would take to enforce their mandate.

For at least the past 18 months, the ordinance has not been enforced. Building Inspector William Sanborn said this week that the program had been abandoned due to staff cuts. The former zoning officer, Maria Dufour, was laid off in August 2006, and a second building inspector was fired last summer, although the latter position was recently filled.

Certainly it takes staffing to enforce a rule like this, which by some estimates covers as many as 1,000 properties around the harbor and along the banks of the Annisquam estuary.

But that is not the only problem. Prior to Dufour's layoff, she had apparently made contact with less than 10 percent of the property owners covered by the ordinance. A computer file located by Sanborn showed 75 contacts, with only about 30 responses.

Then there is the financial burden on the property owner. A structural inspection by an engineering firm costs $1,500 and up. And in one case, where an owner had an inspection done and repairs were recommended, the estimate was more than $100,000, on a piece of property valued at about $500,000.

Finally, even if an owner can afford the repairs, there is little incentive to do so, because development of properties inside the so-called Designated Port Area is so restricted. Sanborn himself sympathizes with those owners, telling reporter Richard Gaines, "Why would I fix it up if I can't make back the investment. What does the (DPA designation) do for the city?"

Mayor Carolyn Kirk has pledged that one of her priorities is to seek rezoning of the DPA. That effort should get the support of the City Council and the city's legislative delegation, since it could remove at least one major barrier to making those buildings safer.

Beyond that, however, city officials must realize that passing an ordinance does not guarantee that anything will change, if it has not also made sure that the department charged with enforcing it has the means to follow through in the long term.