The City Council has improved its proposal to legalize a limited number of tightly regulated bed-and-breakfast operations. It's an issue that for years has elicited a passionate outcry, both from the vacation-rental proprietors who want a place in the visitor market and from opponents who charge that these short-term rentals are too disruptive to neighborhoods.

Bill 7, the legislation that passed a key hurdle this week, offers basically the right approach, by setting stringent limits on what qualifies as a legal B&B. Essentially, these are homes where the owner lives on premises and can rent out no more than three rooms, with off-street parking provided.

There is room for further improvement. Language should be inserted to ensure that the accommodated guests never push the B&B occupancy past the limits of the building and zoning codes. The listed cap of two adults per room, combined with the full-time residents, could still exceed these safety limits.

Overall, though the regulations in the bill should enable the city to focus its oversight energy where it belongs: on the many illegal "transient vacation units" where there is no proprietor to hold accountable for noise and parking disruptions.

The problem is, as always, enforcement. Bill 7 now includes language to require permit numbers to be included in any advertising for the units. It no longer includes the street address — a legitimate concern of the property owners, for security reasons — and city staffers say this does not impede enforcement.

But tracking down the violations and building a case against the more egregious offenders takes a degree of detective skills. Art Challacombe, the city official who oversees this enforcement task, said existing staff are better equipped for the more straightforward task of citing clear-cut violations of the zoning and building codes.

Given that the city is unlikely to have the money to beef up its own staff for the task, the council should consider allowing the work to be self-supporting through fees and fines, and even to be privatized.

The bottom line is that opponents need to be given assurance that even a limited allowance for B&Bs won't simply compound the problem that already exists. The city must show the resolve to shut down unpermitted and unsupervised TVUs, ending the conversion of neighborhoods into mini-resorts.

Oahu ought to be able to host visitors who enjoy the residential environment, provided there is a means to keep it in bounds. The unenforceable status quo, however, represents anything but hospitality. It's an unsustainable overload on Isle communities that intrudes on privacy. That ultimately yields little of the aloha Hawaii visitors are seeking in the first place.