The city administration is taking a two-pronged approach toward regulating rentals on existing residential properties. One bill proposes rules constraining transient vacation units (TVUs), and another would enable accessory dwelling units (ADUs) meant for longer-term tenants.

The TVU legislation would raise revenue to increase the enforce-

ment capabilities of the city’s Department of Planning and Permitting (DPP), a necessary component of any expansion of legal vacation rentals and ADUs as well.

The housing crisis that has exploded in recent years — painfully evident in the homeless encampments springing up around the city — makes it essential to accelerate the passage of Bill 20, which will come up for a second reading Thursday before the Honolulu City Council.

The Council should move the bill along toward final passage. However, elected leaders must be aware that Bill 20 could be enacted well ahead of the more controversial vacation-rental bill, and would lack the enforcement funding.

Regardless, the city must find a way to put a priority on oversight so that landlords abide by the rules rather than convert the dwellings to capture the higher rental income of the vacation units.

Harrison Rue, the city planner shepherding this accessory-dwelling initiative, said the bill would limit the program to landlords who have a covenant registered on the property documents that would limit rentals to terms of six months or longer.

Further, Rue underscored the provision in the bill requiring that one of the dwellings on the lot — either the principal house or the ADU — be occupied by a relative of the landlord.

There are hardship exceptions to that rule, such as illness or active military deployment, making family occupancy impractical, but these exceptions must be cleared by the DPP director.

The ordinance would be broadly aimed at addressing Oahu’s affordable housing shortage, designed to enlist the “local family workforce market,” Rue said. That is a design used in other markets where ADUs have been authorized, and it is the right one for Honolulu.

Opposition to the bill has been based on fears that the ADU permits will proliferate and, even if the landlord is leasing properly to a long-term tenant, the increased density will overtax city roads and sewer systems.

However, the requirement that qualified lots be at least 3,500 square feet in area to accommodate a unit with a maximum of 400 square feet, though it doesn’t eliminate it, at least mitigates that concern.

In addition, the applicant is compelled to get written confirmation from agencies managing sewage, water and access roadways that the infrastructure is sufficient for the added ADU.

The mandate for each rental to come with one off-street stall (some exceptions are allowed for existing legal “ohana” units being converted to accessory units) should minimize the strain on the neighborhood as well.

The public has a right to feel concern about enforcement of these rules, but this is a case where the proverbial perfect should not become the enemy of the good.

One of many supporters of the bill, Kevin Carney of the affordable-housing nonprofit EAH Housing, pointed to the 2011 Hawaii Housing Planning Study, which projected 9,266 rental units needed on Oahu by 2016 for those earning below area median income. Oahu has plainly fallen below that target.

ADUs, he said, “could help us make up for lost time.”

And there’s no more time to lose.