Grease is the sewer camera’s worst enemy for picture quality. In a kitchen branch, a restaurant drain or a lateral downstream of a busy kitchen, congealed fat coats the pipe walls and floor, the head pushes through it, and the lens is smeared within a few feet. The picture goes soft, then milky, then useless, and the operator pulls back to wipe and starts again. This guide covers why it happens, how to keep the lens clear longer and how to read a picture through grease when it cannot be avoided.
Quick answer: fit a skid or centring guide so the lens rides above the grease on the floor; push steadily rather than scrubbing back and forth, which loads the lens; use warm water in the line if the fixtures allow, because warm grease sheds from the lens and cold grease sticks; wipe the lens on retrieval with a soft wet cloth after rinsing, never dry; and where the line is heavily greased, have it jetted first and camera afterwards, which is also the inspection the customer needs. A smeared picture that still shows the pipe’s shape and the counter is still a usable inspection.
Why grease smears the lens
Fat congeals on the cool pipe walls into a soft, sticky layer. The head, slightly cooler than the pipe when it enters, picks it up on the lens window and the LEDs on contact. Unlike water, grease does not run off, and unlike grit it does not scratch; it simply coats. The LEDs then light the smear and the picture becomes a glow with shapes behind it. Kitchen branches, restaurant and cafeteria drains and the lateral downstream of them are the worst; a bathroom-only line is rarely greasy. Grease line inspection covers the commercial case.
Keep the lens off the floor
Grease is thickest on the pipe floor where the head rides. A skid or centring guide that lifts the lens even an inch keeps it out of the worst of it and is the single most effective measure. In a 4 in line the large skid; in a 2 or 3 in branch a small skid or guide spring if the head and pipe allow one. Guide springs and centring guides and guides and skids cover the choice.
Push steadily
A head pushed forward steadily touches the grease once at each point; a head pushed and pulled to work past an obstruction scrubs the lens through the same grease repeatedly. Where the line allows, push through greasy sections without reversing and do the careful looking on the way back when the lens has been wiped. Feeding technique covers the push.
Warm water
Grease at the temperature of the ground is firm and sticky; grease warmed by hot water softens and sheds from a lens. Where the fixtures upstream can be run hot for a few minutes before and during the inspection, the lens stays clearer and the picture improves. Do not pour anything into the line that the camera will meet other than water.
Reading through grease
A greased lens shows a soft, bright, low-contrast picture. Turn the LEDs down; less light on the smear means less glow and more of what is behind it shows. Watch the pipe’s shape rather than its surface: a joint still shows as a ring, a belly as water rising, a root mass as a shadow. The counter still reads. An inspection that establishes the line’s route, the position of joints and a blockage through a greased lens has done most of its job; the surface detail is what is lost. Interpreting footage applies.
Wiping the lens
Rinse first, with water, so any grit in the grease floats off. Then wipe with a soft, wet cloth or a lens cloth; a dry wipe drags grit across the glass. A drop of dish soap on the cloth cuts grease and is rinsed off. Never a solvent, which attacks seals and housings, and never a gloved thumb straight from the rod. Scratched lenses begin with a dry wipe of a greasy lens.
When to jet first
If the picture is lost within a few feet and the operator is wiping every push, the line is too greasy to inspect usefully and the customer needs it cleaned regardless. Jet it, then camera the clean pipe, which is the inspection that shows the wall’s true condition and whether the grease was hiding scale or a defect. A quick camera look before jetting to confirm the pipe can take the jet is still worth doing, greased picture and all. Inspecting before and after jetting covers the order and cleaning a drain before inspection the general case.
Protecting the rest of the reel
Grease on the rod slips the counter wheel and coats the drum. Wipe the rod through a rag on retrieval and clean the wheel afterwards. Cleaning the push cable and counter checks cover the consequences.
Sapphire and coatings
A sapphire window does not resist grease any better than glass; it resists the scratches that come from wiping grease off badly. Some operators apply a hydrophobic coating to the lens window; it helps water shed and does little for grease, and it must be a product safe for the window material. Sapphire vs glass covers the material question.
Common questions
Why does my sewer camera picture go blurry in kitchen drains?
Grease on the lens. Fit a skid, push steadily, run warm water if possible, and wipe with a rinse and a soft wet cloth.
Can I use a solvent to clean grease off the camera lens?
No. Rinse, then a soft wet cloth with a drop of dish soap, rinsed off. Solvents attack seals and housings.
Should a greasy line be jetted before the camera inspection?
If the picture is lost within a few feet, yes. Camera briefly first to confirm the pipe can take the jet, then jet, then inspect the clean pipe.
Related guides
See cameras for root-prone lines, cameras for 4 in pipe, and water inside the head.