What 396.5B-HWSL means in plain language
This violation is issued when an inspector finds that your commercial motor vehicle has a leak somewhere in its fuel system while it is being operated on public roads. That can mean fuel dripping or seeping from a tank, fuel line, fuel filter, injection system component, or any fitting connecting those parts together.
The concern from an enforcement standpoint is straightforward: leaking fuel creates a serious fire hazard for you, your load, other drivers, and the road surface itself. Inspectors are trained to check the entire fuel delivery path from the tank through to the engine during a Level I or Level II inspection, so a small drip that you may not have noticed during your pre-trip can still result in a citation.
It does not matter whether the leak is a slow seep or an active drip — if fuel is escaping the system, the violation applies. That means your pre-trip fuel system check needs to be thorough, not just a glance at the gauge.
What our enforcement data actually shows
The numbers here may surprise you. Across our database of 13 million+ inspections, 396.5B-HWSL has accumulated 21,028 all-time citations, placing it at #132 out of 3,036 FMCSR codes by citation volume. This is not a rare or obscure violation — it is enforced aggressively and consistently across the country.
In the last 12 months alone, our inspection records show 14,152 citations issued under this code, and 3,081 of those came in just the last 90 days. That pace means roughly 34 drivers per day are getting tagged with this violation right now.
The out-of-service picture is especially important to understand. Although 396.5B-HWSL is technically listed as not OOS-eligible under the standard FMCSA framework, our data tells a more complicated story. Of the 21,028 all-time citations in our database, 11,671 resulted in the driver being placed out of service — an OOS rate of 55.5%. Compare that to the all-FMCSR average OOS rate of 31.4% across every code in our database, and this violation sits nearly 25 percentage points above that benchmark. In practice, inspectors are placing drivers out of service at a rate that reflects how seriously they treat active fuel leaks.
Looking at the monthly trend over the last 12 months, enforcement has been consistently high. Citations peaked at 1,438 in August 2025 with 839 OOS placements that same month. There is no slow season for this violation — the data shows citation counts above 1,000 in nine of the last twelve full months tracked.
Who gets cited most
California dominates the state-level data by a wide margin. In the last 180 days, our inspection records show 3,801 citations issued in CA, with 1,248 of those resulting in an OOS placement (a 32.8% OOS rate). If you run lanes through California, this violation should be a top-of-mind pre-trip item every single time.
Kentucky comes in second at 212 citations over the same period, but with a notably higher OOS rate of 46.7% — more than 13 percentage points above California's rate. That gap is material: the same leaking fuel line that earns you a citation and a wave-through in one jurisdiction could park your truck in Kentucky.
Oklahoma rounds out the top three with 180 citations and a 35.6% OOS rate. Beyond these three, the data shows that several states — including TN, MO, UT, and AZ — recorded 100% OOS rates in the last 180 days, meaning every single citation issued there resulted in the driver being placed out of service.
On the carrier side, our data shows fleets such as UNITED PARCEL SERVICE INC (USDOT 21800) with 92 all-time citations and SCHNEIDER NATIONAL CARRIERS INC (USDOT 264184) with 61 citations. The presence of large, well-resourced fleets in this list reflects how widespread fuel system maintenance challenges are across the industry — this is not just a small-carrier problem.
How severe is this compared to similar codes
Within the Vehicle Maintenance category, a few comparisons put 396.5B-HWSL in perspective.
393.9(a) — Inoperable required lamps is the highest-volume peer code in the category with 660,737 all-time citations, but its OOS rate is just 15.4%. Your fuel leak violation has a fraction of those citations but a 55.5% OOS rate — more than three and a half times higher. Inspectors treat visible fuel leaks far more severely than a burned-out marker light.
396.3(a)(1) — Inspection/repair/maintenance - general shows 236,919 citations with a 45.3% OOS rate. That code covers a broad range of maintenance failures, yet 396.5B-HWSL's OOS rate still exceeds it by over 10 percentage points, which tells you how seriously inspectors weigh active fuel leaks specifically.
396.17C-PI — No proof of periodic inspection has 212,081 citations but a 0.0% OOS rate. That is a paperwork problem. A fuel system leak is a hardware problem with real safety consequences, and the enforcement data reflects that distinction clearly.
How to avoid it
The co-occurring violation data from our 13 million+ inspection records is a direct map of what else goes wrong on trucks that get cited for 396.5B-HWSL. Use it as your pre-trip checklist framework.
- Do a complete under-vehicle walk during pre-trip. Look for wet spots, staining, or the smell of diesel under the chassis. Fuel leaks often originate at tank straps, fuel filter housings, or supply and return line fittings — check all of these.
- Inspect your fuel lines end to end. In 90 days of data, 396.5B-L (another fuel system leak code) co-occurred with this violation in 262 shared inspections, meaning multiple fuel system defects were found on the same truck. If one line is seeping, check every fitting.
- Check your brakes thoroughly. Our data shows 393.47E (slack adjuster defective) appeared in 494 shared inspections and 396.3A1-BOS (brakes OOS) appeared in 489 shared inspections alongside this code. A truck leaking fuel is also a truck with brake problems far more often than chance would predict.
- Inspect brake chambers and tubing. 393.47A-BCFSBD (brake chamber cracked/broken) appeared in 278 shared inspections, and 393.45D-B (brake tubing/hoses inadequate) appeared in 257. These are Level I finds — an inspector who spots a fuel leak will keep looking.
- Check steering components. 393.53B-B (steering system components worn) co-occurred in 402 shared inspections. A truck that has deferred fuel system maintenance has often deferred steering maintenance too.
- Know your vehicle make's risk profile. Freightliner variants (FRHT and FREIGHTLIN combined) account for over 8,000 all-time citations under this code — more than any other platform. If you drive a Freightliner, fuel system maintenance is not optional.
- Don't drive fatigued. 392.2-SLLSR appeared in 280 shared inspections. A tired driver skips pre-trip steps — and a missed fuel leak is how a Level I inspection turns into an OOS placement.