Some 70% of Suffolk County homes and businesses still rely on cesspools — but officials are planning to shell out millions to plug those properties into the municipal sewer system.

County Executive Ed Romaine revealed plans to jumpstart a slew of projects with $3.8 million this year alone to modernize the sewer system, and ultimately recycle treated water to irrigate golf courses and other green spaces.

“We’re addressing this crisis with sewer systems that don’t just pump wastewater out to the ocean or the Sound — but systems that actually treat it properly and help protect our aquifer,” Romaine told The Post.

The Republican explained that cesspools and septic tanks aren’t just outdated — they’re dangerous to Long Islanders.

When waste sits underground for too long, it can seep into the soil and contaminate the aquifer beneath us, which is where the county gets all of its drinking water, and when that water gets tainted by human waste, it puts the entire region’s health and safety at risk.

The new system, however, has no timetable to be completed and could take years.

Romaine is now hoping the state and federal government will pitch in for the projects.

Suffolk hasn’t seen a dime from the $4.2 billion Clean Water, Clean Air, and Green Jobs Environmental Bond Act — a massive state fund voters approved back in 2022 to help pay for exactly this kind of infrastructure, the executive said.

Romaine also told The Post that Suffolk County has not received any money the state was supposed to allocate from former President Joe Biden’s $1 trillion infrastructure bill.

“If we have to, we will do this by ourselves,” Romaine told The Post about the possibility of receiving no state or federal funds.

“But it is a shame that the state would abandon Suffolk County in its time of need for environmental purposes,” he added.

The state, however, fired back and said that Suffolk County has received more than $340 million in total grants for water and wastewater infrastructure.

“The Clean Water, Clean Air and Green Jobs Environmental Bond Act is not the only State funding source supporting water infrastructure,” Cecilia Walsh, a spokesperson for the state’s Department of Environmental Conservation, told The Post.

“New York State has consistently and historically provided Suffolk County with record amounts of clean water infrastructure funding for septic systems from a variety of sources,” Walsh added, “since 2017, funding to Suffolk County through the Septic System Replacement Program totals an estimated $60 million and of the total statewide funding committed to local governments for this program, Suffolk County received two thirds of the total $90 million allocation.”