Sometime next month, if all goes well, the Suffolk legislature will take an important vote. Lawmakers will weigh in on a plan from county officials to help homeowners replace failing septic systems with new technology to greatly reduce the amount of nitrogen that is fouling Long Island’s waters.

They should say yes.

That doesn’t mean the plan is perfect, or that it can’t be improved. But it is sensible, and county officials say they are open to changes that make it better. Legislators should examine it closely during Tuesday’s public hearing, propose whatever tweaks they think necessary — and then push it forward. Long Island has lived too long with nasty tides, closed beaches, dead fish, foul smells and vanishing marshes.

Suffolk’s program has come a long way since a disastrous rollout by officials a year ago. The county has been working with manufacturers, testing and approving systems for use, and licensing installers. It has prioritized areas to be upgraded based on how quickly wastewater reaches bodies of water, an approach that makes sense. So areas around Lake Ronkonkoma, the Carmans River and Georgica Pond would go first.

To cover design and installation costs that could reach $17,850 per home for a new high-tech system, Suffolk is pitching a blend of county grants of up to $10,000 and low-cost 15-year loans to homeowners through the Community Development Corp. of Long Island. That’s fair; homeowners should have some buy-in since the value of their homes will increase.

Suffolk plans to fund the program with $2 million a year from a county reserve fund as authorized by the public in an earlier referendum. That would pay for about 400 installations over the first two years. Even if Suffolk were to receive all of the $75 million included in the recently approved state budget for septic replacements statewide, which it won’t, that still would cover only another 7,500 systems over the next five years. That’s not enough. The county has 360,000 homes not connected to sewers, and they are by far the biggest contributor to nitrogen pollution. Nearly 70 percent of the nitrogen in Great South Bay, for example, comes from septic and cesspool systems.

advertisement | advertise on newsday

So as big a step forward as this plan would be, it still requires a reliable funding stream, like the water usage fee that would be set by a referendum Suffolk officials want to put before voters for their approval. The $50 million a year that would raise would allow more home septic systems to be swapped out. It also would give the wastewater treatment industry confidence that the money would be there so it could drop its prices closer to Suffolk’s goal of $10,000 per unit. That was the experience in states like Maryland that have pioneered what Suffolk is trying to do. Cheaper prices stretch precious dollars.

All of which means that state lawmakers — led by Long Island’s delegation in the State Senate — ultimately must approve legislation to let Suffolk residents vote on the referendum. That would turn a good program into a game-changer. Suffolk must start its program and make it work so that state legislators can see it in action and finally have no excuse for not getting on board. — The editorial board