Sewer Camera Pipe Size Checker

How head size and pipe diameter fit together

A sewer camera head has to travel the pipe, turn its bends, and still sit near the centre so the picture stays lit and level. Pipe diameter decides which head can do that. Most residential drains fall into a few sizes, and each one favours a different head. Match the two well and the camera glides. Mismatch them and the head either jams in a bend or rattles along the pipe floor with half the wall in shadow.

Head diameter is quoted in millimetres. The common classes are 17mm, 23mm, 25mm, and 30mm. Smaller heads clear tighter turns. Larger heads centre themselves in wide pipe and carry more light. The checker above maps your stated pipe size to the head class that clears it, so you are not guessing from a product photo.

Pipe sizes you will actually meet

Branch lines under a sink or toilet often run 1.5 to 2 inches. These are the tightest runs in a house. A 17mm head is usually the only size that turns their sharp elbows without wedging. Push a 25mm head in and it can encounter severe friction in tight fittings depending on bend radius and fitting geometry.

Household drain lines and short laterals commonly sit at 3 to 4 inches. This is the sweet spot for a 23mm or 25mm head. The head is small enough to pass a 3 inch cleanout yet large enough to stay centred, so the light reaches the pipe wall evenly.

Main sewer lines and larger laterals run 4 to 6 inches, sometimes wider. Here a 25mm or 30mm head earns its size. In a 6 inch pipe a small head drifts along the bottom, so half the frame is dark water and the crown of the pipe never gets inspected. A bigger head with a spring or a self-levelling collar rides closer to the middle.

Why an oversized head fails

Bigger is not safer. An oversized head cannot follow a tight radius. It stalls at the bend, and pushing harder only kinks the cable behind it. You then lose the run and risk the rod. When a line mixes sizes, for example a 2 inch branch feeding a 4 inch stack, size the head to the smallest section it must pass, not the widest.

Why an undersized head disappoints

A tiny head in a wide pipe reads clearly but sees little. It sits low, so standing water blurs the lens and the pipe crown stays hidden. Cracks and root intrusion often start at the top of the pipe, which is exactly the part a low, small head misses. In 4 inch and larger lines, a head sized to the pipe finds more of what you are looking for.

Self-levelling and centring features

Some cameras keep the image upright with a weighted self-levelling head. This matters most in wider pipe, where the head can roll. Spring guides and skid collars push the head off the pipe floor so the view stays central. Neither feature replaces correct sizing, but both extend how well one head copes across a range of diameters.

Frequently asked questions

What head size fits a 4 inch sewer pipe?

A 23mm or 25mm head suits most 4 inch drains. It passes a standard cleanout and still sits near the centre. A 30mm head works too if the whole run stays at 4 inches or wider with gentle bends.

Can one camera cover 2 inch and 4 inch pipe?

A 17mm head is the safest single choice when a job spans both. It clears the 2 inch branches and still returns a usable picture in 4 inch line, though it sits lower than an ideal 4 inch head would.

Does a bigger head give a better picture?

Only when the pipe is wide enough for it. In matched pipe a larger head carries more light and centres better, which does improve the image. In narrow pipe the same head jams, so the best picture comes from the head that fits, not the largest one available.