Cesspools and Sewers in Nassau County: Connection Rules and Replacement Grants

Two sets of rules govern wastewater for a North Shore house. Where a public sewer exists, Nassau County’s health ordinance sets the connection timeline; where it does not, the home runs on a private system, and a state fund reimburses part of the cost to replace a cesspool. More buying guides cover inspections, closing costs and the other line items.

When Nassau County requires a sewer connection

The Nassau County Public Health Ordinance defines a Public Sewer System as the pipes and conduits that convey sewage to a location for treatment and disposal, controlled by a governmental agency. An Individual Sewerage System is septic tanks and sub-surface leaching facilities with a maximum design capacity of 30,000 gallons per day serving a single parcel. The full ordinance text used here is the June 2014 copy.

Separately, the ordinance bars anyone from constructing or maintaining a privy, cesspool, sewage disposal system, pipe or drain so as to expose or discharge sewage to the atmosphere or the ground surface, or into any storm sewer or drain, or so as to endanger a drinking water supply. No private sewage disposal facilities may be built under or within a building without special permission from the health department. It also allows exceptions. Individual sewerage systems may be approved for new single family subdivisions in a Special Groundwater Protection Area, under conditions.

How a cesspool works

A cesspool is a drywell that receives untreated sanitary waste containing human excreta, sometimes with an open bottom or perforated sides. Older versions were built like a dry well lined with loose-fitting brick or stone and disposed of sewage by infiltration into the soil.

Liquids leak out through the soil as conditions allow, while solids decay and collect at the base. As solids accumulate, they block the escape of liquids and the cesspool drains slowly or overflows. A deep cesspool can let raw sewage enter groundwater with minimal biological cleansing, which can lead to groundwater pollution and undrinkable water supplies.

The word is not used uniformly. Cesspit, cesspool and soak pit describe either an underground holding tank sealed at the bottom or a soak pit that is not sealed. In North America, a closed tank for temporary storage of sewage is simply called a holding tank.

How a septic system differs

A septic tank is a buried, watertight tank designed to receive and partially treat raw domestic wastewater. Heavy solids settle to the bottom while greases and lighter solids float to the top. The solids stay in the tank and the wastewater is discharged to the drainfield for further treatment and dispersal.

A conventional system is a septic tank plus a trench or bed subsurface infiltration area, known as a drainfield, and it is typically installed at a single-family home or small business. Design and size vary with household size, soil type, site slope, lot size and local regulations.

Alternatives exist for difficult sites. Mound systems are an option where soil is shallow, groundwater is high or bedrock is shallow. Sand filter systems can be built above or below ground. An aerobic treatment unit injects oxygen into the treatment tank, and regular life-time maintenance should be expected for it. Gravelless drainfields have been widely used for over 30 years in many states. The EPA overview of septic system types describes each.

Grants to replace a cesspool

The Clean Water Infrastructure Act of 2017 created the Septic System Replacement Fund, which funds counties to help homeowners replace cesspools and repair or replace septic systems. Only participating counties receive funds. The state’s program outline is dated December 2025.

An enhanced system must be designed to reduce total nitrogen in treated effluent to 19 mg/L. A septic project in Nassau or Suffolk must reduce effluent nitrogen to 19 mg/L or less, and in those counties only systems that reach 19 mg/L are eligible for State funding. The Nassau County Soil and Water Conservation District administers the SEPTIC program, which draws on the State Septic Replacement Program and federal sources.

Eligibility has limits. Single and two-family homes and small businesses qualify only with an existing design sewage flow not exceeding 1,000 gallons per day. New construction is not eligible, and connecting a home to a public sewer does not count as a septic project. Funded work must comply with local permitting jurisdictions such as local health departments, and replacements should routinely meet the standards of Appendix 75-A.

How the state fund pays out

A participating county notifies eligible property owners that funds are available, and an owner who undertakes a septic project may then apply to the county. Once the award letter is accepted, the owner may hire a design professional and contractor to do the work. Funding is on a reimbursement basis, so the owner is initially responsible for the total cost of the project. The owner may choose to have the reimbursement paid directly to the contractor.

To be reimbursed, the owner submits a request that includes cost documentation and invoices for eligible costs. The county reviews the request, approves, modifies or denies it, and issues payment to the owner or the contractor. Design costs are eligible but limited to the work needed to complete an approved design, including site investigation, as-built drawings and inspections.

What the fund does not cover

Routine maintenance such as a pump-out of a septic tank is not reimbursable. Neither are government permit fees, including fees for building permits, zoning permits, construction compliance certifications and floodplain disturbance permits. Sewer connection costs are not eligible. Replacing a cesspool with another cesspool is not eligible. Enhanced septic system projects, where the technology is commercially available, are preferred.

When a system counts as failing

A county decides eligibility, and septic systems within 250 feet of a listed waterbody qualify when they are failing or reasonably likely to fail. The outline lists the conditions that point to a failing system. A septic tank that needs pumping four times or more a year is one. A cesspool with no separate septic tank for primary solids separation is another. So is an absorption area within two feet of the seasonal high groundwater level, or within 100 feet of an individual well or 200 feet of a public water supply.

The fund targets Priority Geographic Areas within participating counties that contain groundwater supplies, drinking water supplies and stressed or impaired surface waters. As of the DEC’s 2025 summary, Point Lookout was one of the few areas on Nassau County’s south shore that remained unsewered, relying on outdated cesspools and septic systems. The home inspection guide covers what a licensed inspector examines in an older house.