A Beginner's Glossary: Grease, Drain & Vacuum Terms Decoded

Why a glossary?

The first time a vendor says "your interceptor is past the 25% rule" or "we need access to the cleanout," most people just nod. Don't nod. Here's what the terms actually mean, so you can ask smarter questions and not get talked past.

The pipes themselves

• Lateral — The pipe running from your building out to the city main under the street. Responsibility depends on the property and lease, but it surprises owners all the time.
• Mainline — Inside a building, the main drain that all your fixtures empty into before it leaves as the lateral. Outside, "the main" can also refer to the city sewer under the street.
• Branch line — A smaller line serving one or two fixtures (like the line from your kitchen sink to where it joins the main).
• Stack — A vertical waste or vent pipe inside the building.
• Vent — Pipe that lets air into the drainage system so water can flow correctly.

Access points

• Cleanout — A capped access point on a drain line. The threaded plug we pull off to send a snake, rod, or jetter down. Every property should have at least one accessible. If yours doesn't, installing one will save you money on every future call.
• P-trap — The U-shaped pipe under a sink. Holds water that blocks sewer gas from coming up.
• Floor drain — Open drain in a basement, bathroom, or commercial kitchen floor. Has a trap too, and that trap dries out if it's not used regularly.

The bad stuff

• FOG — Fats, Oils, and Grease. The single biggest cause of commercial sewer problems. Municipalities have legal limits.
• Biofilm — A slimy bacterial layer that grows on the inside of any drain line. Catches everything else.
• Scale — Mineral deposits (like calcium) that build up inside pipes over years, narrowing the diameter.
• Root intrusion — Tree roots that grow into pipe joints chasing moisture.
• Belly / sag — A low spot where the pipe has settled, so water and solids pool there instead of flowing.
• Backup — Sewage going the wrong way: out of a floor drain, up into a tub, back into a sink. Always means a blockage downstream.

The tools you'll hear about

• Snake / cable / auger — A flexible steel cable spun through the line to bore through clogs. Quick, cheap, good for one-off blockages.
• Power rodder — A bigger, motorized version of a snake with cutting heads. For roots and heavy debris in mainlines. See power rodding.
• Hydro jetter — A truck-mounted machine that sends high-pressure water down the line through specialized nozzles. Scours the pipe wall clean. See hydro jetting.
• Sewer camera — A self-leveling color camera on a flexible push rod. Records video of the inside of the line. The honest answer to "what's actually wrong." See camera inspection.
• Locator — A wand that picks up a transmitter on the camera head and marks the exact spot and depth on the ground above the problem. Required before any digging.
• Vacuum / pumper truck — A big tank truck that vacuums out grease traps, pits, basins, lift stations, and large sludge.

Commercial / industrial terms

• Grease trap / grease interceptor — A box (either under the sink or buried outside) that catches FOG before it enters the sewer. Required for any food service.
• Lift station — A pit with pumps that lifts wastewater up to a higher elevation when gravity won't carry it.
• Catch basin — An outdoor drain that catches storm water (and sediment, leaves, debris). Common in parking lots.
• Manifest — The paperwork showing what was pumped, how much, where it was disposed. Required for compliance. Keep them.
• MS4 — Municipal Separate Storm Sewer System. A federal compliance program for stormwater. Affects commercial properties with parking lots.
• BOD / TSS — Biological Oxygen Demand and Total Suspended Solids. Pollutant measurements that determine if you're in compliance with your sewer discharge permit.

Service & billing terms

• Trip charge / service call — Flat fee for showing up. Often credited toward the work.
• Net-30 — Standard commercial invoice terms: you have 30 days to pay.
• W-9 — IRS form your vendor provides so you can pay them as a business expense.
• COI (Certificate of Insurance) — Proof a vendor is insured. Property managers should require this before letting any vendor on site.
• Camera & jet — Industry shorthand for the gold-standard combo: camera the line, jet it, camera it again to verify.

Quick rule of thumb

Any time you don't understand a term on a quote or an invoice, ask. A real professional will be glad to explain it in plain English.