Who owns the sewer line between your house and the street

Updated October 30, 2026 · 3-minute read · Old House Sewer Lines

In Westchester County, the property owner is responsible for the sewer line from the house to the public sewer main, and the city, town or village owns the main. The county's Department of Environmental Facilities describes "a lateral line, which is the responsibility of the property owner, into a sewer main owned, operated, and maintained by the local municipality" (Westchester County DEF). Exactly where the owner's share ends depends on local wording, and as of October 2026 only four municipalities in southern Westchester publish it in a form this site could confirm.

A curving street of large early-1900s houses, led by a steep-roofed Tudor-style house.

What the towns have put in writing

Mount Vernon's sewer management plan says the city has no ownership of individual sewer services and that each homeowner answers for the service line up to the point where it meets the city sewer. The same plan says the city has no lateral replacement program (City of Mount Vernon CMOM plan). Details are in Mount Vernon's lateral rules.

Rye and the Village of Mamaroneck go furthest. Their codes stretch the lateral from the building out to the public sanitary sewer main, then assign every repair, replacement and bit of upkeep on it to the owner alone (Rye §§ 161-16 and 161-17A; Village of Mamaroneck §§ 282-13 and 282-14A). The exact text is compared in how Rye and Mamaroneck define the lateral.

Yonkers is less precise. Its Water Bureau page says "many" homeowners are responsible for the water and sewer service lines on their property between the house and the city mains, and cites no code section (City of Yonkers Water Bureau). See Yonkers sewer laterals.

Published ownership wording, southern Westchester (as of October 2026)
Municipality	What the published text says	Type of document
Mount Vernon	Homeowner answers for the service up to where it meets the city pipe	City CMOM plan, 2021, updated 2023
City of Rye	Lateral runs from the building to the public main; owner solely responsible	City code §§ 161-16, 161-17A
Village of Mamaroneck	Same definition; owner solely responsible	Village code §§ 282-13, 282-14A
Yonkers	"Many" homeowners responsible for service lines on their property	City web page, no code section
New Rochelle, White Plains, Scarsdale and others	Not confirmed	Ask the town

Where the wording stops

No published text found for this site says in plain words that the owner's share includes the tap on the main or the stretch beneath the roadway. Rye and the Village of Mamaroneck run the lateral to the public main; Mount Vernon runs it to the connection with the city sewer. If a repair would cross the street, ask the town's public works or engineering office in writing before work starts.

For New Rochelle, White Plains, Scarsdale, Bronxville, Pelham, Pelham Manor, Larchmont, the Town of Mamaroneck, Eastchester and Tuckahoe, no primary text could be confirmed. That does not mean those places have no rule. How to check a town without a published rule lists the questions to ask.

Why the split matters

When the main is blocked, the municipality's crew clears it. When the lateral is blocked, the owner hires a plumber or sewer contractor; main or lateral covers how crews tell the difference. Anything installed on the lateral belongs to the owner too. FEMA's urban flooding guidance says a backwater valve is part of the lateral and "will not be maintained by the municipality" (FEMA).

Background

State code splits the owner's piping in two. The building drain ends 30 inches beyond the exterior walls; the building sewer runs from there to the public sewer (NYS Department of State). From the municipal main, sewage moves into a county district trunk sewer and on to a treatment plant run by the county, as described in Westchester's county sewer districts.

House to main, in three pieces

Building drainInside the house, ending 30 inches past the exterior walls
LateralThe responsibility of the property owner
Sewer mainOwned, operated and maintained by the local municipality

Westchester County Department of Environmental Facilities description; building drain length from the state code definitions. Exact limits vary by town.

Key facts

County wording: the owner answers for the lateral, and the local municipality owns, operates and maintains the main (Westchester County DEF).
In Rye (§ 161-17A) and the Village of Mamaroneck (§ 282-14A), fixing or replacing a lateral is a job for the owner only.
Mount Vernon's plan says the city has no lateral replacement program (CMOM plan).
Yonkers says "many" homeowners are responsible for their service lines (City of Yonkers).
The building drain extends 30 inches past the exterior walls; the building sewer starts there (NYS DOS).
UDig NY member utilities do not mark private facilities (UDig NY).