📋 Quick Facts — Plumbing Permit in St. Louis
| Detail | Info |
|---|---|
| Permit Required? | Yes — in most cases |
| Permit Type | Plumbing Permit |
| Permit Office | City of St. Louis Building Division |
| Phone | (314) 622-3313 |
| Hours | Mon–Fri business hours |
| Online Portal | Apply Online |
| Fee / Timeline | Current Data |
|---|---|
| Plumbing Permit Fee | Plumbing permit: $90 flat. |
| Approval Time | Simple residential: 1–5 days. New online portal launched 2025. |
| NEC Edition (MO) | 2017 |
| Permit Authority | Local level. St. Louis example given as reference — varies by county. |
Do I Need a Plumbing Permit in St. Louis?
The short answer: almost always yes. REQUIRED for any work on a plumbing system beyond simple fixture replacement — and St. Louis is no exception. The City of St. Louis Building Division enforces plumbing permit requirements for residential and commercial work.
✅ Work That Always Requires a Permit
- Water heater replacement (gas or electric)
- New plumbing rough-in (new supply and drain lines)
- Moving existing plumbing supply or drain lines
- Adding new plumbing fixtures (sink, toilet, shower)
- Water service line replacement
- Sewer lateral repair or replacement
- Gas line work (new or modification)
⚠️ Work That May Be Exempt
- Replacing a faucet on an existing supply line (no pipe work)
- Replacing a toilet on existing rough-in (some jurisdictions)
- Clearing a drain clog (maintenance work)
💰 Plumbing Permit Fees in St. Louis (2026)
Permit fees in St. Louis are set by City of St. Louis Building Division. Here's the current fee structure for plumbing work:
| Fee Item | Amount |
|---|---|
| Plumbing Permit | Plumbing permit: $90 flat. |
City of St. Louis is an INDEPENDENT CITY — completely separate from St. Louis County. Very different fees. City fees are among the lowest in the country.
* Fees may change. Always verify current rates with City of St. Louis Building Division at https://www.stlouis-mo.gov/government/departments/public-safety/building.
🔍 Inspection Requirements
After the permit is issued, St. Louis requires inspections at key stages. Do not cover work before it's inspected.
- Rough-in Inspection: Inspector checks all supply and drain lines before walls are closed. Pipe material, slope of drain lines (1/4 inch per foot minimum), proper venting, and water test.
- Final Inspection: Verifies all fixtures are installed and functioning, water heater is properly vented and strapped, T&P valve discharge is correct, no leaks.
📝 How to Apply for a Plumbing Permit in St. Louis
- Verify your contractor is licensed — Licensed plumber (state-specific license) in most states. Some states allow homeowners for owner-occupied single-family homes. Plumber's license required in CA, FL, TX, NY, IL, PA, and most major states..
- Gather required documents — Equipment specs, site plan, load calculations where applicable.
- Submit the application — Online at City of St. Louis Building Division or in person.
- Pay the permit fee — Plumbing permit: $90 flat..
- Post the permit — Keep a copy on-site until all inspections pass.
- Schedule inspections — Do not cover work until the inspector signs off.
📌 Missouri State Requirements
In addition to St. Louis's local rules, these state-level requirements apply:
- Kansas City and St. Louis have own permit offices and stricter enforcement
- Most of Missouri is local jurisdiction — rural areas may have minimal enforcement
- Missouri HVAC Authority: missourihvacauthority.com for HVAC license info
🚫 Common Plumbing Permit Mistakes in St. Louis
- Skipping the permit on water heater replacement — most common unlicensed plumbing violation
- Wrong T&P valve discharge pipe material (CPVC not allowed in some jurisdictions — must be copper or galvanized)
- Missing expansion tank on closed systems (required when backflow preventer is present)
- Not strapping water heater in seismic zones
💡 Pro Tips from Contractors
- Water heater permits are usually same-day, over the counter — takes 15 minutes to pull
- In CA: seismic strapping is strictly enforced — both upper and lower straps required, specific heights
- Gas water heaters need B-vent inspection before firing up — confirm with inspector
- In most cities, you can pull the permit online same day — no need to go to the building department
Notes specific to St. Louis:
- CRITICAL: City of St. Louis and St. Louis County are TWO SEPARATE JURISDICTIONS. Most suburbs are in the county, not the city.
- City of St. Louis fees are very low — HVAC ~$105, electrical $85, plumbing $90
- Mechanical fees are flat per-unit: furnace $40, condensing unit $40 each
- Building permit for projects over $3,000: $10 per $1,000 + $25 application fee
Get Your Exact Plumbing Permit Requirements in 5 Seconds
Our AI searches live building department data for St. Louis and all 50 states — returning the exact permit requirements, fees, and application links for your job. No hold music. No guessing.
Run a Free Permit Check →❓ Frequently Asked Questions
Do I need a plumbing permit in St. Louis, MO?
Yes, in most cases. REQUIRED for any work on a plumbing system beyond simple fixture replacement. In St. Louis, contact City of St. Louis Building Division at https://www.stlouis-mo.gov/government/departments/public-safety/building.
How much does a plumbing permit cost in St. Louis?
In St. Louis: Plumbing permit: $90 flat.. Fees may change — always confirm with City of St. Louis Building Division before applying.
How long does a plumbing permit take in St. Louis?
Simple residential: 1–5 days. New online portal launched 2025.. Simple residential trade work is often issued same-day or within 1–3 business days.
Who can pull a plumbing permit in Missouri?
Licensed plumber (state-specific license) in most states. Some states allow homeowners for owner-occupied single-family homes. Plumber's license required in CA, FL, TX, NY, IL, PA, and most major states.