Septic system installation and replacement in Nassau and Suffolk County.
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Septic systems are common throughout Long Island, especially in areas without municipal sewer. We install septic systems for new construction and replace aging or failing systems.
A properly installed septic system starts with the right tank size, placement, and drainage design. We evaluate your property and household needs to help determine the right setup.
Compare with cesspool installation, protect your investment with septic tank pumping, and read Septic System Installation in Brookhaven: Law & Costs and Commercial Septic Installation in Riverhead.
New construction, an aging tank, or a failing drainage field may call for a new septic system. If you’re dealing with recurring backups, standing wastewater, or ongoing system problems, an evaluation can help determine whether replacement is needed.
How is a septic tank different from a cesspool? A septic tank separates solids from wastewater before sending the liquid to a leach field. A cesspool collects waste in a chamber that allows liquid to seep into the surrounding soil.
What size septic tank do I need? The right size depends on your home’s bedroom count, expected wastewater use, and local requirements. We evaluate these factors when planning your installation.
Can you replace an existing septic system? Yes. We evaluate your existing system and property to plan a replacement suited to your home’s needs.
Real jobs. Real results. Long Island homeowners and businesses trust Drastic Drainage.
Suffolk County offers grants up to $45,000 for qualifying septic installations, and we walk you through every step, from permit to final inspection.
Three decades of septic installations across Suffolk County means we know the soil, the regulations, and the SCDHS process cold.
We handle site prep, excavation, installation, and health department coordination, no subcontractors, no handoffs, no confusion about who's responsible.
We carry the Suffolk County Liquid Waste License, $1 million in liability insurance, and a $10,000 bond, required by law, verified by us.
After every job, you get full installation documentation, critical for SCDHS compliance, SIP grant applications, and future property sales.
What You're Actually Dealing With Here
More than 360,000 homes in Suffolk County still run on aging cesspools that don't properly treat wastewater. If yours is one of them, you're not just dealing with an inconvenience. You may be facing a compliance issue, a barrier to selling your home, or a system that's quietly contaminating the same groundwater your family drinks.
Suffolk County sits atop a sole-source aquifer. There's no backup water supply. What goes into the ground here stays here.
Since July 1, 2021, Suffolk County has required Innovative and Alternative Onsite Wastewater Treatment Systems, I/A OWTS, for new construction and major renovations. Enforcement is tightening. If you've been putting this off, the clock is moving faster than it used to. The good news: between Suffolk County and New York State grant programs, the cost of a new system may be covered almost entirely. We can help you figure out where you stand.
What a Proper Installation Actually Gets You
A compliant, functioning septic system isn't just a legal checkbox. It protects your property, your health, and your ability to sell when the time comes.
You can sell your home without a failing system derailing the inspection or the closing.
Your family's drinking water isn't being contaminated by nitrogen leaching from a decades-old cesspool beneath your yard.
You stop worrying every time it rains hard that the water table will push sewage back into your home.
You're positioned to access up to $45,000 in combined State and County grant funding before the program fills up.
You get full installation records you can hand to a buyer, a lender, or the health department without scrambling.
You're done coordinating between an engineer, a permitting consultant, and a separate installer. We handle all of it.
The Grant Money Is Real, Most Homeowners Miss It
As of July 2025, Suffolk County homeowners upgrading to a qualifying I/A OWTS system can access combined grants from Suffolk County and New York State totaling up to $45,000. The average cost of a nitrogen-reducing I/A OWTS installation in Suffolk County runs approximately $25,000, including engineering and permits.
That math means many homeowners end up paying nothing out of pocket, and some come out ahead. The program is run through Suffolk County's Septic Improvement Program, and applications go through reclaimourtwater.info. Homeowners who can't cover remaining costs after the grant may also qualify for a CDCLI loan, up to $10,000 at 3% interest over 15 years.
Here's the catch most people don't hear about: the grant only applies if your installer is on the Suffolk County SIP Approved Installer List. That's a separate qualification from simply holding a Liquid Waste License. If you're planning to apply for grant funding, make sure you confirm your contractor's status on that list before signing anything.
What the Installation Process Actually Includes
A septic installation in Suffolk County isn't just digging a hole and dropping in a tank. It starts with a site assessment and soil evaluation, because the sandy soils along the South Shore drain very differently than the heavier soils you'll find in parts of Smithtown or Huntington.
From there, a licensed engineer produces the system design, and we submit the permit application to the Suffolk County Department of Health Services. Once the permit is approved, installation on a straightforward system typically takes one to three business days.
We handle excavation, system placement, and all required SCDHS inspections before the system is backfilled, skipping that inspection step is how other contractors create serious problems for homeowners down the road. After sign-off, we provide you with complete installation records. Whether you're in Bay Shore, Patchogue, Sayville, Riverhead, or anywhere else in Suffolk County, the process is the same: one crew, no gaps, no surprises.
From First Call to Final Sign-Off
We come out, look at your property, evaluate your current system, and tell you exactly what you're working with, no pressure, no upselling.
We coordinate soil testing, engineer drawings, and the full SCDHS permit application so you don't have to navigate the health department alone.
Our crew handles excavation, system installation, and the required health department inspection, then hands you complete installation records when the job is done.
Septic System Installation Questions, Answered Straight
It depends on the type of system you need. A conventional septic system in Suffolk County typically runs between $10,000 and $20,000. An I/A OWTS, the nitrogen-reducing system now required for new construction and major renovations, generally costs between $15,000 and $30,000, including engineering and permits. Suffolk County permit fees alone can range from roughly $330 to $2,000 depending on system complexity. That said, the Suffolk County Septic Improvement Program currently offers combined State and County grants of up to $45,000 for eligible homeowners installing qualifying I/A OWTS systems. For many Suffolk County homeowners, that grant covers the entire project cost. The only way to know what your specific situation looks like is to get an assessment, which is why we offer free estimates.
I/A OWTS stands for Innovative and Alternative Onsite Wastewater Treatment System. Unlike a conventional septic system or a cesspool, an I/A OWTS includes an advanced treatment unit that removes nitrogen from wastewater before it enters the ground. This matters in Suffolk County because the county sits atop a sole-source aquifer. Its only drinking water supply, and nitrogen from aging cesspools and septic systems is the largest documented cause of water quality degradation in local bays like Great South Bay and Peconic Bay. As of July 1, 2021, I/A OWTS systems are required for new construction and for major reconstruction projects where renovation costs equal or exceed 50% of the structure's market value. If you're planning a significant addition or gut renovation, that threshold is worth knowing before you start pulling permits.
No. Suffolk County banned new cesspool-only installations in 2019. If your current cesspool fails or needs replacement, you'll be required to install a compliant septic system, and depending on your property's situation, that may mean an I/A OWTS rather than a conventional system. Many homeowners don't realize this until they're already in the middle of a repair call or a home sale. The distinction matters because the permitting process, the cost, and the contractor qualifications required are all different for a cesspool versus a compliant septic system versus an I/A OWTS. If you're not sure what your property currently has or what a replacement would require, a site visit is the fastest way to get a clear answer.
The Suffolk County Septic Improvement Program offers grants for homeowners replacing outdated cesspools or septic systems with qualifying I/A OWTS systems. To be eligible, your property generally needs to be a residential home in Suffolk County, have no outstanding tax liens, and have a valid Certificate of Occupancy. Properties near bays, harbors, and surface water bodies (including communities along Great South Bay, Peconic Bay, and Shinnecock Bay) are often given priority consideration. Applications are submitted through reclaimourtwater.info. One important detail: the grant only applies when you use a contractor on the Suffolk County SIP Approved Installer List. That's a separate designation from simply being a licensed cesspool contractor. If accessing grant funding is part of your plan, confirm your installer's status on that list before the project begins.
For a straightforward installation on a property where permits are already approved, the physical work typically takes one to three business days. The longer part of the timeline is usually the permitting process, submitting the application to the Suffolk County Department of Health Services, waiting for review, and coordinating any required soil testing or engineer drawings beforehand. An experienced contractor who submits complete, accurate applications can move through that process more efficiently than one who's less familiar with SCDHS requirements. We've been navigating Suffolk County's permitting process for over 30 years, which means we know what the health department needs and how to avoid the back-and-forth that delays less experienced applicants.
Excavation is part of the process. There's no way around that. But how much disruption you're left with afterward depends on the crew doing the work and how they approach the job. We've been doing this across Suffolk County for over 30 years, from tight residential lots in West Babylon and Babylon to larger properties in Smithtown, Hauppauge, and out toward Riverhead and the East End. We know how to work around irrigation systems, driveways, and existing landscaping where possible, and we're straightforward with homeowners about what the excavation footprint will look like before we start. The SCDHS inspection also has to happen before we backfill, so the system is verified correct before anything is covered. That's not just a rule; it's how you avoid having to dig everything back up later.
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