The Direct Answer
In many U.S. counties, an above-ground residential propane tank under 125 gallons does not require a dedicated LP tank installation permit. This is the most common threshold — set in county-adopted versions of NFPA 58 and the International Fuel Gas Code — and it reflects the lower risk profile of smaller, easily visible, easily moved above-ground containers.
However, "no LP tank permit" does not mean "no permit at all." Even where no tank installation permit is required, the gas piping that connects the tank to your home almost always requires a gas piping permit from the building department. These are different permits, and the gas piping permit requirement applies at virtually every tank size.
And the absolute rule — repeated here because it is misunderstood so often — is that underground propane tanks always require a permit, regardless of size, regardless of county, regardless of lease arrangement.
Even if your county exempts your tank size from an LP installation permit, you almost certainly still need a gas piping permit for the supply line from the tank to your home. Homeowners who learn "no permit needed for the tank" and proceed without any permits at all are still violating code — and face the same insurance and resale consequences. Always ask your building department about both the tank permit and the gas piping permit.
The Four Factors That Determine Your Permit Requirement
Factor 1: Tank Size
Tank size is the primary trigger for LP tank installation permits. Here is how it typically breaks down nationally:
| Tank Size | Above-Ground Permit Status | Underground Permit Status | Gas Piping Permit? |
|---|---|---|---|
| Under 125 gal | Often not required (verify locally) | Always required | Yes, almost always |
| 125–250 gal | Varies by county — often required | Always required | Yes, almost always |
| 251–500 gal | Required in most jurisdictions | Always required | Yes |
| 500+ gal | Required everywhere | Always required | Yes |
Factor 2: Above-Ground vs. Underground
This is the clearest dividing line in LP gas permitting. Above-ground tanks have size-based permit thresholds that vary by county. Underground tanks have no threshold — they always require a permit. The moment you choose to bury your tank, the "do I need a permit?" question is answered: yes, always, everywhere.
Factor 3: Your County's Adopted Code
The 125-gallon threshold is common but not universal. Some counties set their permit trigger lower (at any permanent LP installation regardless of size). Some counties — primarily rural ones that have not adopted a residential building code — have no permit requirement at all for above-ground residential tanks. The only way to know for certain is to call your county building department or fire marshal's office and ask directly.
Here is a breakdown of common county approaches:
| County Type | Typical Permit Threshold | How to Verify |
|---|---|---|
| Large city (Houston, Atlanta, etc.) | Any permanent LP installation regardless of size | City building department website or permit portal |
| Suburban county with adopted IFC/NFPA 58 | 125 gallons above-ground; all underground | County building department — call or website |
| Small city with own code | Varies — sometimes 60 gal, sometimes 125 gal | City building or fire department |
| Rural unincorporated county (code adopted) | Usually 125 gal above-ground; all underground | County building or fire marshal |
| Rural unincorporated county (no code) | Often no permit required for above-ground residential | Call county judge's office or fire marshal |
Factor 4: Leased vs. Owned Tank
If you lease your tank from a propane supplier, the supplier's installation crew typically handles all required permits as part of their service. This does not change whether a permit is required — it changes who is responsible for obtaining it. If you own the tank outright, you (or your licensed contractor) are responsible for permits.
Important: even if your supplier says "we handle the permits," ask them to confirm in writing which permits they will obtain. Some suppliers handle the LP tank permit but leave the gas piping permit to you or your plumber. Get clarity on this before installation day.
Genuine Exemptions — When No Permit Is Actually Required
Setting aside underground tanks (always permitted) and large tanks (always permitted), here are the genuine scenarios where no LP gas permit may be required:
1. Small above-ground tanks in rural no-code counties
On unincorporated rural property in a county that has not adopted a residential building code, a homeowner may install an above-ground propane tank of typical residential size (250–500 gallons) without obtaining a tank installation permit. This is legally permissible in those counties. It is still advisable to verify with the county fire marshal, and the gas piping still requires a plumbing/gas permit in most cases.
2. Tanks under 125 gallons in counties with the standard threshold
In counties that set their permit trigger at 125 gallons (the most common threshold), an above-ground tank smaller than 125 gallons — such as a standard 100-gallon or 80-gallon tank used for a single appliance — does not require an LP tank installation permit. A gas piping permit for the supply line is still typically required.
3. Exchange cylinders and portable tanks
Standard portable propane cylinders — the type you exchange at hardware stores and gas stations — are exempt from permit requirements at any size up to DOT-regulated portable cylinder capacity (typically up to 40 lb / approximately 9-gallon capacity). These are treated as consumer products, not permanent installations, and are not covered by LP installation codes.
When "No Permit Needed" Creates Problems Anyway
Even when no permit is legally required for a tank installation, proceeding without documentation can create problems in these situations:
Homeowner's insurance
Your homeowner's insurance policy may include a clause requiring permitted installation of fuel-burning equipment and associated fuel storage. Even if your county doesn't require a permit, your insurance carrier might. Review your policy or call your agent before installation to ask whether a propane tank installation needs to be documented and reported to maintain your coverage.
Property sale disclosure
When you sell your home, you will typically need to disclose the presence of a propane tank. The buyer's home inspector will note the tank. In many states, real estate disclosure laws require disclosure of unpermitted improvements. If your county required a permit and you didn't get one, this creates a title and disclosure issue. If your county did not require a permit, document that fact (keep a copy of your communication with the county confirming no permit was needed) so you can demonstrate compliance at resale.
Refinancing and home equity
Some mortgage lenders require confirmation that major home systems — including LP gas installations — were installed to code and with required permits. This is more commonly an issue for larger tanks and whole-home systems, but can arise for any propane installation.
The Right Process Regardless of Whether a Permit Is Required
Whether or not your county requires a permit, the best practice for any residential propane tank installation is:
- Use a licensed LP gas contractor. Even where no permit is required, a licensed installer knows the NFPA 58 setback rules, proper connections, and safe installation practices. An unlicensed installation may be cheaper but creates liability and insurance problems.
- Verify setbacks. Even without a permit and inspection, NFPA 58 setback requirements represent the engineering standard for safe propane tank placement. They apply regardless of permit status.
- Document everything. Keep the installer's invoice, their license number, the tank manufacturer's data sheet, and any written communication from your county confirming permit status. This documentation protects you at resale and for insurance claims.
- Call 811 before any excavation. Even if you're placing an above-ground tank with no excavation needed for the tank itself, the gas piping trench to the house requires 811 utility clearance.
Underground tank? → Permit required. Period. No exceptions.
Above-ground, 500+ gallons? → Permit required in virtually every jurisdiction.
Above-ground, 125–499 gallons? → Probably required. Verify with your county.
Above-ground, under 125 gallons? → Often not required. Still need gas piping permit. Verify locally.
Portable exchange cylinder? → No permit required.
If a permit is required by your county, yes — it is still required even when your propane supplier installs the tank. The supplier's installation crew typically obtains the required permits as part of their service, but the legal requirement for the permit does not change based on who installs the tank. Ask your supplier specifically which permits they will obtain for your installation and get confirmation in writing.
Replacing an existing tank with a larger one often triggers a new permit requirement even if the original installation was exempt. If you are moving from a 100-gallon tank (exempt from permits in your county) to a 500-gallon tank (above the permit threshold), the larger tank installation requires a permit. This is treated as a new installation, not a like-for-like replacement. Also note that a larger tank may require gas piping upgrades (larger diameter supply line) which require their own permit.
If discovered — through a neighbor complaint, a routine fire inspection, or an inspector on your property for another job — you will likely be required to obtain a retroactive permit, pay a penalty fee (often 2–3× the standard permit fee), and have the installation inspected. If the installation does not meet code, you may be required to have it corrected at your expense. Beyond enforcement consequences, an unpermitted installation can void homeowner's insurance coverage and create resale complications. The permit cost ($50–$150) is trivial compared to these risks.