Do I Have Septic or Sewer? How to Tell in 5 Minutes

Whether you just bought a home, are considering a purchase, or have simply never looked into it, knowing whether your property is on septic or city sewer is one of the most practically important things a homeowner can know. The answer affects your maintenance responsibilities, your costs, your home sale disclosures, and who to call when something goes wrong with your drains.

In the Central Valley — including unincorporated areas of Stanislaus and Merced Counties — the split between septic and sewer is more nuanced than in urban areas. Newer subdivisions may be on city sewer while adjacent rural parcels use private septic. Some older neighborhoods within city limits are still on septic. This guide gives you five reliable ways to determine which applies to your property.

Method 1: Check Your Utility Bill

The fastest starting point is your monthly water or utility bill. If you have city sewer service, it will appear as a line item on your bill — usually labeled 'Sewer,' 'Wastewater,' or 'Sewer Service Charge.' It may appear on your water bill or as a separate utility bill depending on your city.

• Modesto: Sewer charges appear on the Modesto Irrigation District (MID) or city utility bill as 'Wastewater'
• Turlock: Appears on Turlock's city utility bill as 'Sewer Services'
• Merced: Appears on City of Merced utility bill as 'Sewer'
• Stockton: Appears on the Municipal Utilities Department bill
• Unincorporated county areas: No sewer line item = almost certainly on septic

If you see no sewer or wastewater charge on any of your utility bills, and you're not in a property with a shared community system, you are almost certainly on a private septic system.

Method 2: Search County or City Permit Records

If your property has a septic system, it should have a permit on file with the county. Stanislaus County Environmental Health Division and Merced County Environmental Health Division maintain permit records for all onsite wastewater treatment systems (OWTS) — what regulators call septic systems.

• Stanislaus County EHD: Search online at ehd.stancounty.com or call (209) 525-6700
• Merced County EHD: Search online at countyofmerced.com or call (209) 381-1100
• You'll need the property address or Assessor Parcel Number (APN)
• Records show permit date, system type, tank size, and installation location
• If no OWTS permit exists and the property predates public sewer extension, verify with the city whether sewer was available at the time of construction

If a septic permit exists for your property, you're on septic. If no permit exists, the property either predates permit requirements (possible for properties built before the 1970s), is on city sewer, or has an unrecorded system (which is a separate problem you'll want to address).

Method 3: Look for Physical Clues on the Property

Even without records, several physical signs tell you which system you have:

Signs You Have a Septic System

• Riser lids in the yard: Green or black plastic lids (6–24 inches diameter) flush with or slightly above grade are septic tank access points
• Drain field area: A section of yard (usually 20×50 feet or larger) that may have slightly greener grass, slight mounding, or a pattern of parallel lines
• Cleanout T at or near the foundation: A 4-inch PVC pipe with a threaded cap extending from the ground near the house foundation, angled toward the yard rather than toward a street
• No sewer lateral at the street: Properties on city sewer have a sewer lateral running from the house to a pipe under the street. If you see no city access point or manhole near your property line, you may be on septic.
• Backyard tank shape: If you probe the ground with a thin metal rod (septic technicians do this routinely), a solid obstruction 18–48 inches down indicates a buried tank

Signs You Have City Sewer

• Cleanout at or near foundation facing the street (not the back yard)
• Sewer lateral running to a manhole or city-accessible point at the property line or street
• City sewer manhole cover visible in the street or alley near your property
• No area of the yard that looks like a drain field (no parallel buried pipe pattern)
• Property is on a city lot under 1/4 acre in an established urban neighborhood — though this is not conclusive

Method 4: Check Your Home Inspection Report or Disclosure Documents

If you purchased your home and received a home inspection report, it should note whether the property has a septic system. Look for sections labeled 'Plumbing,' 'Sewage Disposal,' or 'Onsite Wastewater System.' A proper home inspection should identify the waste disposal method.

In California, sellers are required to disclose known material facts about the property under Civil Code 1102. Septic system ownership is a material fact. Your Transfer Disclosure Statement (TDS) or Seller Property Questionnaire should indicate whether a septic system exists. If you have these documents from your purchase, they are a reliable reference.

Additionally, your title insurance company or escrow officer may have noted septic system information in the preliminary title report. If you can access these purchase documents, check them before searching county records.

Method 5: Call the City or County Utility Department

If the methods above haven't given you a clear answer, a direct call to the city or county utility department will. Tell them your address and ask: 'Is this property connected to the city sewer system?' They can check their connection records and give you a definitive answer in minutes.

• City of Modesto Public Works: (209) 577-5268
• City of Turlock Public Works: (209) 668-5570
• City of Merced Public Works: (209) 385-6800
• City of Stockton Municipal Utilities: (209) 937-8831
• City of Tracy Public Works: (209) 831-6300
• Stanislaus County Environmental Health: (209) 525-6700
• Merced County Environmental Health: (209) 381-1100

Why It Matters: Septic vs. Sewer Responsibilities

Once you know which system you have, understanding your responsibilities is straightforward:

If You Have a Septic System

• You are responsible for all maintenance, repairs, and replacement of the system
• Routine pump-outs every 3–5 years are required (every 1–3 years for larger households)
• You must follow county health codes for what can be discharged into the system
• Repairs and replacements require county permits
• You must disclose the system to buyers when you sell
• No monthly sewer fee is charged by the city

If You Have City Sewer

• The city owns and maintains the public sewer main in the street
• You are responsible for the sewer lateral from your house to the property line (rules vary by city)
• You pay a monthly sewer or wastewater fee on your utility bill
• No pump-outs are required — wastewater flows to the municipal treatment plant
• Emergency backups may qualify for city assistance if caused by main line failure

Special Situations in the Central Valley

The Central Valley has several common situations that can make the septic-or-sewer question less straightforward:

• City-adjacent rural parcels: Properties on large lots at the edge of city limits often appear urban but may be on septic — this is common in areas around Modesto, Turlock, and Merced
• Older city properties on septic: Some homes within city limits predate sewer extension and were never connected — and may still be on septic unless proactively connected
• Recently annexed areas: As cities expand, newly annexed rural areas may have a sewer connection option but not be required to connect immediately. Some of these properties remain on septic for years after annexation.
• Agricultural parcels with residential structures: Farm properties often have both a septic system for the residence and separate agricultural waste management — the residential septic system may be smaller than expected for a large parcel
• Pre-1970 properties with incomplete records: Older rural homes may have septic systems that predate county permit requirements, meaning no permit exists even though the system is operational

What to Do Once You Know

If you've confirmed you're on septic and don't know the last time the system was serviced, scheduling an inspection and pump-out is the right first step. This tells you the current condition of the tank, whether the baffles and effluent filter are intact, and how quickly solids have accumulated.

If you've confirmed you're on city sewer and notice slow drains or backups, the issue is in the sewer lateral from your house to the street — and a plumber or rooter service is the right call, not a septic company.

Frequently Asked Questions

Can a property have both septic and city sewer?

Rarely, but it can happen. Some properties were connected to city sewer at a later date but still have an old septic system on the parcel. The old system should have been decommissioned (pumped, filled with sand or slurry, and the county notified). If you find an old tank on a property that's been connected to sewer, have it properly abandoned.

Do I have to connect to city sewer if it becomes available?

In most California jurisdictions, connection to city sewer is required when the main extends to within a certain distance of your property — typically 200 feet — and your existing septic system fails or needs major repair. Mandatory connection for currently functioning septic systems is less common but does occur in some sensitive groundwater areas. Check with your county EHD or city planning department if you're in an area where sewer is being extended.

My neighbors have sewer — why don't I?

Sewer availability depends on when each parcel was developed relative to when sewer main infrastructure was built in the area. In mixed neighborhoods, some properties may have connected to sewer when the main was extended, while adjacent parcels on different lot configurations or built at different times remained on septic. This is common at the edges of Central Valley cities.

Can I switch from septic to city sewer?

If a city sewer main runs within 200 feet of your property, you can typically apply to connect. The process involves a connection fee (often $5,000–$15,000 in Central Valley cities), permit fees, installation of a sewer lateral to the street, and decommissioning of the existing septic system. Call your city's public works department to confirm availability and costs.

Does being on septic affect my property value?

A well-maintained septic system is not a negative for rural and semi-rural property values in the Central Valley. Buyers in these markets expect septic systems and factor in lower utility bills (no monthly sewer fee) as a partial offset to maintenance costs. A failing or aging system, however, does reduce value — which is why inspection before sale is strongly recommended.