Septic-to-Sewer Conversion Permits

A front yard trench with a new sewer lateral pipe running from a house to the street, old septic tank lid exposed

Short answer: switching from septic to sewer usually takes three approvals: a sewer or utility connection permit, a plumbing permit for the house-to-sewer line, and a health-department abandonment of the old tank (pump, crush or rupture, fill, inspect). Florida gives you 90 days to abandon the tank after connecting; King County, Washington, gives 30 days.

When the sewer main finally reaches your street, switching off the septic tank sounds like a single plumbing job.

In practice it is usually three related projects: connecting the house to the public sewer, pulling a plumbing permit for that work, and properly abandoning the old tank so it cannot hold sewage or collapse under a lawn later. Miss any one of those pieces and the conversion is incomplete—even if the toilets flush into the street overnight.

PermitCove is an independent homeowner guide, not a government agency. The city and county examples below belong to the places named next to them. Confirm fees, licensed-contractor rules, and abandonment deadlines with your local sewer utility, building department, and health department before you dig. See our disclaimer.

Why conversion is not a septic repair—and not a lateral-only job

Homeowners often confuse three different scopes:

Septic repair or replacement keeps an onsite sewage system in service. You are still treating wastewater on the lot.
Private sewer-lateral replacement fixes or swaps the pipe between the house and an existing public sewer connection (or the cleanout that already serves the house). That is a utility/plumbing problem, not a septic conversion. See our guide to private sewer line replacement permits when that is the real scope.
Septic-to-sewer conversion hooks the building plumbing to public sewer and takes the old septic system out of service under health rules—usually by pumping, crushing or rupturing the tank so it cannot hold water, filling it, and getting an abandonment inspection.

If your contractor’s bid only lists “connect to cleanout” and never mentions pumping or filling the tank, ask them to rewrite the scope. Utility connection without abandonment leaves a buried vessel that many health codes still treat as an unfinished job.

If the septic system is staying and only needs repair, see septic repair permits.

The typical permit stack

Expect more than one counter. The exact names differ by county, but the stack is consistent:

Sewer / utility connection approval. Permission (and often a capacity or system-development charge) to join the public sewer. In unincorporated Gwinnett County, Georgia, that is a Septic to Sewer Permit from the Department of Water Resources (DWR).
Plumbing (or building) permit. The physical house-to-cleanout or house-to-main work, inspected by building or plumbing staff. Gwinnett’s procedure requires a separate Plumbing Only Permit from Planning & Development’s Building Permits Division after the DWR permit is in hand.
Septic abandonment / health permit. Local health or environmental health approval to pump, open or crush the tank, fill it, and inspect the abandonment. Florida’s statewide rule and county DOH pages treat this as its own tracked step; Fairfax County, Virginia, tells you to contact the Health Department when abandoning a septic field.

Licensed plumbers usually pull the plumbing piece. Septic abandonment may require a licensed septic tank contractor, a state-licensed plumber, or—in some Florida counties—an owner-occupant on an owner-occupied home. Ask both desks who may sign the applications before you hire.

Residential yard trench connecting a house sewer line to a green public sewer cleanout stub near the street

Connecting the house line to a public sewer cleanout or stub is the utility half of a septic-to-sewer conversion—not the same job as repairing a septic drainfield.

What happens to the old tank

Once the house is on sewer, an unused septic tank is a buried container that can fill with water, cave in, or leak. Abandonment rules exist so the tank is emptied and disabled, not just “left in the ground.”

Florida Admin Code Rule 62-6.011 is a clear statewide pattern: after connection to sanitary sewer (or after a tank is discontinued), the onsite system must be abandoned within 90 days. The owner or agent applies for an abandonment permit and pays the required fee; a permitted septage company pumps the tank and provides a receipt (or certifies the tank was empty and dry); the bottom is opened or ruptured—or the tank collapsed—so it cannot retain water; the tank is filled with clean sand or other suitable material and covered with soil; then the department, utility, or plumbing authority inspects the abandonment.

Hillsborough County, Florida (DOH) publishes a local abandonment packet that matches that sequence: application and site plan, a $50 fee payable to DOH-Hillsborough (as published on their page), work limited to licensed septic contractors, state-licensed plumbers, or owner-occupants on owner-occupied properties, pump receipt, crush or cave the tank bottom (or punch holes so it cannot hold water), call for inspection after fill, and flag the street and tank location. Do not leave an open hole.

King County, Washington sewer-connection guidance tells homeowners that contractor bids for sewer connection should include septic decommissioning—pumping and cleaning existing tanks and filling or removing them per Title 13. King County Board of Health Code 13.04.054 requires that anyone permanently removing a septic tank (or other OSS wastewater tank) from service shall, within 30 days: have the septage removed by an approved pumper; remove or destroy the lid; fill the void with compacted soil or gravel; and report the abandonment to the health officer on the required form with the fee specified in the fee schedule.

Gwinnett County, Georgia folds tank work into the septic-to-sewer construction scope itself: the licensed plumber’s estimate must cover connecting to the yard cleanout and emptying and crushing the existing septic tank or filling it with concrete or gravel. Building inspections include a second visit after the tank is cleaned and crushed.

Licensed septage hauler vacuum truck with coiled green suction hoses, typical of equipment used to pump a residential septic tank

Pumping by a permitted septage company—and keeping the receipt—is usually step one of legal tank abandonment after you connect to sewer.

Opened concrete septic tank lid with soil fill visible inside the hatch during abandonment

After pumping, codes typically require rupturing or crushing the tank so it cannot hold water, then filling it with sand, gravel, or other suitable material before inspection.

Septic-to-sewer rules compared

Jurisdiction	Permits named	Tank abandonment rule	Published detail
Gwinnett County, GA	DWR Septic to Sewer Permit + Plumbing Only Permit	Plumber empties and crushes the tank or fills it with concrete or gravel; second inspection after	¾-inch meter example: $4,172; Plumbing Only fee 0.6% of estimate, $30 minimum
Fairfax County, VA	Permit to connect to public sanitary sewer	Contact the Health Department when abandoning a septic field	Sewer "available" within 300 ft of a single-family home
King County, WA	Sewer connection through the utility	Within 30 days: pump, remove or destroy lid, fill, report to health officer	Connection required within 200 ft when a trigger applies
Florida (Rule 62-6.011)	Abandonment permit	Within 90 days of connection: pump, rupture or collapse, fill, inspect	Hillsborough County fee: $50 (as published)

Sources: Gwinnett County DWR, Fairfax County, King County FAQ, King County Title 13, Fla. Admin. Code 62-6.011, DOH-Hillsborough.

City and county walkthroughs

Gwinnett County, Georgia (unincorporated) — DWR septic-to-sewer procedure

Gwinnett’s published residential procedure applies when a cleanout is already in the yard and the neighborhood sewer project is complete. You need both a Septic to Sewer Permit from DWR and a Plumbing Only Permit from Planning & Development Building Permits. Work cannot start until both are acquired.

Get a licensed plumber’s estimate first (many homeowners collect more than one). Pay DWR fees at the Central Facility in Lawrenceville based on meter size. For a typical ¾-inch residential meter, Gwinnett’s published figure is $4,172 ($4,147 System Development Charge + $25 permit fee). That is Gwinnett’s published example for that meter size—not a national average—and the county notes fees may change; call the DWR Permits Desk at 678-376-6887 to verify current amounts before you write a check.

Give the DWR permit to your licensed plumber. The plumber then obtains the Plumbing Only Permit (address/parcel info, license numbers, estimate). The Plumbing Only fee is 0.6% of the construction estimate, minimum $30. Two inspections are required: one for the connection to the sewer cleanout, and one after the septic tank is cleaned out and crushed. For septic-tank questions, Gwinnett points homeowners to Environmental Health at 770-963-5132.

Fairfax County, Virginia — connect to public sanitary sewer

Fairfax requires a permit to connect a building to the public sanitary sewer when service is available. Only a licensed plumber may obtain a permit to tap the sewer main; if an existing spur is present, the homeowner may connect to that spur and install the line to the house, with the permit issued by Land Development Services. All required sanitary sewer fees must be paid before the permit issues.

Availability distances under Fairfax County Code Chapter 65, Article 6: for single-family homes (attached or detached), a sanitary sewer main is considered available when within 300 feet of the building; for other building types, within 500 feet. If you are abandoning a septic field as part of the switch, Fairfax directs you to contact the Health Department at 703-246-2201 (TTY 711).

King County, Washington — when connection is required

Under King County Board of Health Title 13 and related county code (as explained in Public Health’s sewer-connection FAQ), connection to public sewer is required when the property is inside the Urban Growth Area, the city or sewer utility allows connection, the property is within 200 feet of public sewer (shortest legal route), and one of several triggers applies—such as new construction, creating new lots, repairing or replacing a failing onsite system that cannot meet current standards, or certain remodels and ADU work that affect the septic system. Distance is measured along rights-of-way and easements; get a Sewer Availability Certificate or written confirmation from the utility before you budget.

Bid scopes commonly include design, utility fees and capacity charges, side-sewer construction, surface restoration, and septic decommissioning. Costs vary widely by utility and lot layout; King County’s FAQ deliberately does not publish a single “average connection price,” and neither should a national blog.

Florida abandonment timing (statewide + Hillsborough example)

After sewer connection, Florida Rule 62-6.011’s 90-day abandonment clock is the statewide baseline. Hillsborough County’s DOH page is a concrete local packet: forms, site plan, $50 fee (as published there), licensed parties who may perform the work, pump receipt, crush/fill, inspection, and flags at the street and tank. Other Florida counties follow the same rule with their own fee schedules—ask your county DOH for the current abandonment application.

Open sewer connection trench with concrete structure and a plumbing permit inspection clipboard ready for the inspector

Leave the connection trench open for the plumbing inspection—and keep the utility and abandonment permits with the job packet so each desk can see the other approvals.

Practical homeowner checklist

Confirm sewer is actually available to your lot (stub/cleanout in place, availability certificate, or utility letter). Ask whether connection is optional or mandatory for your situation.
Write one clear scope for every bid: “Connect building sewer to public sewer at [cleanout/main/spur]; pump and abandon existing septic tank per health code; restore yard.”
Identify the three desks: sewer utility / DWR, building or plumbing permits, and environmental health for tank abandonment.
Ask who may pull each permit—licensed plumber, licensed septic contractor, owner-occupant—and whether one contractor can cover both connection and abandonment.
Collect written fee quotes from the utility (connection/capacity/system charges) and from building/health for permit and inspection fees. Treat published examples such as Gwinnett’s ¾-inch figure or Hillsborough’s $50 abandonment fee as local snapshots; call to verify.
Call 811 before excavation. Coordinate street or right-of-way work separately if the tap crosses public pavement.
Schedule the connection inspection before the trench is backfilled.
Pump the tank through a permitted septage company; keep the receipt for the health inspector.
Crush, rupture, or collapse the tank as required; fill with approved material; call for the abandonment inspection within your local deadline (for example, Florida’s 90 days or King County’s 30-day abandonment timing under Title 13).
Keep finaled permits and pump/abandonment records with the house file—buyers and lenders often ask.

If you are still mapping which counter owns which step, use the 10-minute AHJ permit checklist and ask the same scope question at utility, building, and health. For related plumbing DIY vs licensed-contractor rules, see plumbing and gas line permits. When abandonment involves significant excavation or structure removal beyond the tank, our demolition permits guide can help you spot whether a separate demo track applies—though most septic abandonments are health/plumbing jobs, not full building demolitions.

FAQ

Do I have to connect to sewer when it reaches my street?

It depends on local rules. In King County, connection is required when the property is in the Urban Growth Area, within 200 feet of public sewer, and a trigger applies, such as new construction or a failing septic system (King County FAQ).

Can I leave the old septic tank in the ground?

Only if it is properly abandoned. Florida requires the tank to be pumped, opened or collapsed so it cannot hold water, filled, and inspected within 90 days of connecting (Rule 62-6.011).

Who can pull the sewer connection permit?

In Fairfax County, only a licensed plumber may get a permit to tap the sewer main; a homeowner may connect to an existing spur (Fairfax County). In Gwinnett, the licensed plumber gets the Plumbing Only Permit.

How many inspections are there?

Gwinnett requires two: one for the connection to the sewer cleanout and one after the tank is cleaned out and crushed (Gwinnett DWR). The health department may inspect the abandonment separately.

Bottom line

Septic-to-sewer conversion is a hookup plus a plumbing permit plus a legal tank abandonment—not a septic repair and not a private-lateral swap alone. Use local procedures as your checklist: Gwinnett’s dual DWR and Plumbing Only permits with two inspections; Fairfax’s connection permit, licensed main tap, and Health Department call for septic abandonment; King County’s distance and UGA triggers with decommissioning in the bid; Florida’s pump-crush-fill-inspect sequence within 90 days. Verify every fee and deadline with the offices that will inspect your yard before the first shovel goes in.

Last checked: October 31, 2026.

Official sources

PermitCove is an independent guide for U.S. homeowners. It is not a government agency. Always confirm current sewer-connection, plumbing, and septic-abandonment rules with your local utility, building department, and health department before you convert from septic to public sewer.

Edited by Ahmed Khalifa, founder of PermitCove. Sources are linked inline; see our Editorial Policy.

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