What is an AVO inspection?

AVO stands for audible, visual, and olfactory. The inspector walks the site and checks equipment for leaks by listening, looking, and smelling, without an optical gas imaging camera or other instrument.

What should an AVO inspection record include?

Record the site, the inspector, the date and time, and the result for each equipment group. For each leak, record the component, the date of the first repair attempt, the date the repair was completed, and the reason for any delay. Keep a record of inspections that found no leaks as well.

How often are AVO inspections required?

It depends on the site type and on which rule applies. Under the current OOOOb rule, single wellhead and small well sites need AVO at least quarterly, and well sites with major production equipment need it every two months alongside OGI surveys. EPA's October 2026 proposal would set quarterly AVO for marginal well sites, but it is not final and the current schedule still applies. Confirm the frequency in your monitoring plan.

Can a pumper do the AVO inspection?

AVO inspections need no camera, so many operators have the pumper do them during a regular site visit. The pumper needs to know what to check and how to record it, and the record has to reach the office.

Does BasinCheck file the EPA annual report?

No. BasinCheck keeps the inspection and repair records. You or your environmental consultant still prepare the annual report in EPA's reporting template.

Field Checklist Template

AVO Inspection Checklist for Well Sites and Tank Batteries

Walking the location is the easy part of an AVO inspection. The hard part comes months later, when you have to show that every visit happened and every leak was repaired. This checklist covers the equipment a pumper checks by ear, eye, and nose, and keeps each leak tied to its repair.

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Wellhead: valves, connectors, flanges, open-ended lines
Tanks: thief hatches, gaskets, vent lines, relief valves
Vessels: separators, heater treaters, dump valves

Works offline in the field Audit-ready records

AVO Leak Inspection

Synced

Wellhead valves, connectors, and flangesPass

Thief hatches closed and seatedIssue

Closed vent system and relief valvesPass

Flare pilot lit and control device workingPass

Separators, heater treaters, and dump valvesPass

4 of 5 checks passedcorrective action created

Field status

Saved offline · syncs on reconnect

Interactive checklist

Work through the field-ready essentials

0 of 10 checked

Field workflow

How to use this checklist

Match it to your site

Remove equipment you do not have and add what is missing. A pumping unit on electricity needs a shorter list than a site with a compressor.

Walk the location

Listen, look, and smell at each piece of equipment. Carry your gas monitor and follow your H2S procedures. No reading is worth an exposure.

Record the visit either way

Submit the inspection even when you find no leaks. A clean inspection with a date and a name is still evidence.

Track each leak to repair

Give every leak an owner and a due date inside your repair deadline. Record the first attempt and the finished repair.

Built for the job

What to include in an AVO inspection checklist

An AVO record has to answer four questions later: who inspected, where, when, and what happened to each leak.

Site and inspector details

Company, location or pad name, county, coordinates if your plan calls for them, inspector name, and the date and time of the walk.

Wellhead, flowlines, and vessels

Valves, connectors, flanges, flowlines, separators, heater treaters, meter runs, and dump valves that may be stuck open.

Tanks and closed vent system

Thief hatches closed and seated, gaskets intact, and no vapor or odor at vent lines, relief valves, or piping to the control device.

Flare, controllers, and pumps

Pilot flame present, control device working, and no process controller or pneumatic pump stuck venting.

Repair record for each leak

The component, the date of the first repair attempt, whether it worked, the date the repair was finished, and the reason for any delay.

Components you could not inspect

Anything skipped because it was unsafe or difficult to reach, named on the record so the office knows what the visit did not cover.

Compliance & proof

This checklist is a starting point

EPA's fugitive emissions rules for oil and gas well sites, 40 CFR Part 60 Subparts OOOOb and OOOOc, rely on AVO inspections at many sites. A proposal published on October 29, 2026 would set quarterly AVO inspections as the fugitive emissions standard for marginal well sites, which it defines as sites producing 15 barrels of oil equivalent per day or less. EPA also proposed a second option that applies the same standard to conventional well sites, and it could finalize either one. Until EPA finalizes a rule, the current schedule applies. Check your own obligations with your environmental advisor.

It does not replace your fugitive emissions monitoring plan or the rule text. Survey frequency and repair deadlines depend on your site type and on which subpart applies.

One record per site visit, with date, time, and inspector
Each leak named by component, with repair dates through to completion
Clean inspections kept alongside the ones with findings

Questions from the field

AVO inspection checklist FAQ

When binders stop scaling

Run this checklist on a phone

BasinCheck saves each AVO inspection with the inspector, time, and location, works without signal, and turns every leak into a corrective action with an owner and a due date.

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In BasinCheck

Inspection and JSA connected

Failed item assigned and tracked

Evidence retained for review

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