The lens window on a sewer camera head is the one optical surface between the sensor and the sewer, and it is dragged along pipe floors covered in sand, scale and grit for the life of the head. Every head accumulates fine scratches. Most never matter. Some, usually from one careless moment rather than years of use, put a haze or a line across the picture that no cleaning removes. This guide covers how scratches happen, when they matter and what the options are.
Quick answer: fine scratches from normal use scatter a little light and are invisible in the picture; a deep scratch or a scuffed patch across the centre shows as a haze, a line or a flare from the LEDs that is there in every pipe. Prevention is a skid or guide that lifts the lens off the pipe floor, a cap in storage, and never wiping grit across the glass. A scratched lens is not repaired; the head is replaced, or on some reels the lens window is. Tell a scratch from fog or dirt by cleaning the lens and looking at it in good light with the LEDs off.
How lenses scratch
Dragging the head along the floor of a pipe with sand or scale in it, which a bare head does on every push. Pushing into a blockage of grit or glass. Wiping the lens with a gloved thumb that has grit on it, which is the single most common cause of a serious scratch. Storing the head face-down on foam that has collected grit. Retrieving the head through a cast iron hub with sharp scale.
When scratches matter
Fine, random scratches across the glass scatter a small fraction of the light and have no visible effect; every used head has them. A deep scratch across the centre shows as a line in every picture. A patch of scuffing shows as a haze that softens detail and catches the LED light as a glow, worst in a dark pipe with the LEDs at full. When the picture in a clean, dry pipe is hazy or has a fixed line and cleaning does not change it, the lens is the cause. Blurry footage has other causes to rule out first.
Scratch, fog or dirt
Clean the lens properly with water and a soft cloth, dry it, and look at it in daylight with the LEDs off. Dirt is gone. Fog on the outside is gone; fog that remains is inside the head and is water, not a scratch, and means a seal has failed. Scratches are visible as lines or a frosted patch in the glass itself. Water inside the head covers the fog case and greasy lenses the dirt case.
Prevention: skids and guides
A skid or centring guide lifts the head off the pipe floor so the lens does not plough through the grit, and it is the single most effective protection. Use one in any pipe large enough to take it. Guides and skids explains which to use where.
Prevention: cleaning technique
Rinse the lens with water before anything touches it, so the grit floats off rather than being dragged across the glass. Then wipe with a clean, soft, wet cloth. Never wipe a dry, gritty lens, never with a glove that has handled the rod, never with paper towel from the van floor. Cleaning after a sewage job puts this in sequence.
Prevention: storage
Cap the head or store it face-up in clean foam. Shake grit out of the case foam periodically. A head stored face-down in grit for a season comes out scratched without ever entering a pipe. Storage covers it.
Sapphire versus glass
Some heads carry a sapphire lens window, which is far harder than glass and resists scratching from sand and scale; others carry hardened glass. A sapphire window is a real advantage for a working head and is worth noting on a listing. Sapphire vs glass covers the difference.
Polishing
Fine haze on a glass window can sometimes be reduced with a plastic or glass polishing compound and a soft cloth, working gently and keeping compound away from the seal. It will not remove a deep scratch and it can make a sapphire window worse by scratching it with the compound. For most heads the effort is better spent on replacement.
Replacing the lens or the head
A few makers sell the lens window as a part that a repairer can swap; most sell the whole head. A replacement head is a few hundred dollars on budget reels and more on professional ones, and it is a plug-in job on reels designed for it. Reels with replaceable heads and when to replace a head cover the decision, and repair vs replacement the economics.
Common questions
Can a scratched sewer camera lens be fixed?
Fine haze on glass can sometimes be polished. A deep scratch cannot; the head or the lens window is replaced.
How do I know if the lens is scratched or just dirty?
Clean it with water and a soft cloth, dry it, and look at the glass in daylight. Scratches stay; dirt goes; fog that stays is inside the head.
How do I stop my sewer camera lens scratching?
Use a skid, rinse before wiping, never wipe grit across the glass, and cap the head in storage.
Related guides
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