By Matthew Baring-Gould, Kingscliff-based drainage plumber. Servicing Tweed Heads for 4 years. 5.0 stars across 173 Google reviews. Licensed NSW 383340C and QLD 15036450. ABN 74 605 392 348.

Blocked sewer at a Tweed Heads West property. Hydrojetted from the toilet penetration at the back right of the house, hit something hard just outside the bathroom window. Got some water flow. Sand pulling back on the jet was the diagnostic that the line was broken and ground was entering. Also hydrojetted from the inspection opening at the front of the house (which had its screws missing) and got upstream for a short distance. Two sections of broken pipe located and marked with blue paint.

What the customer called us for

Owner called us out for a blocked sewer. Toilet was backing up and they could not clear it themselves.

What we found when we got there

Classic broken-sewer symptom pattern. Jet from the toilet penetration got blocked at a hard object just outside the bathroom window. Got some water flowing but the key tell was sand pulling back on the jet, which means ground is entering the pipe through a break somewhere upstream. From the front inspection opening (missing its screw cap, which is common on older properties), the jet got upstream for a short distance before hitting resistance. Two separate broken sections marked on the surface.

Why we did it this way

Sand ingress on the jet is one of the cleanest diagnostic signals in drain work. A sealed pipe does not let sand or fine debris in. If sand is coming back, the pipe is open to the ground somewhere. Two separate stop points on the jet, from two different access points, means two separate broken sections. On an older property, the pipe is typically earthenware or clay, which gets brittle and cracks over decades of ground movement. The right fix is to dig and replace the broken sections, or on some runs, reline them.

What we did on site

1. Attended site and investigated the blocked sewer.
2. Entered the hydrojet down the toilet penetration at the back right of the house.
3. Hit a hard object just outside the bathroom window and documented the stop point.
4. Continued jetting and got some water flow, confirming partial clearance.
5. Noted sand pulling back on the jet as the broken-pipe signal.
6. Entered the hydrojet from the front inspection opening (which had its screw cap missing).
7. Got upstream for a short distance before hitting the second resistance point.
8. Marked both broken sections with blue paint on the surface.
9. Documented findings and recommended repair or replacement of the affected sections.

The result

Partial flow restored, but the line is broken in two places and will keep causing problems until fixed. Owner has both break locations marked on the surface and the diagnostic in writing.

If you have the same issue

If your sewer blocks and the jet pulls back sand or fine dirt, you have a broken pipe. Jetting alone will not fix it. Each time the line blocks it will block again sooner because the break keeps getting bigger as ground movement works it open. The cheaper fix is always to repair while the breaks are small. Call Matty on 0447 188 394 or request a quote.

Customer names and addresses have been withheld. Individual results vary. Drain Masters Plumbing is licensed in NSW (383340C) and QLD (15036450).

Frequently asked

Why does sand coming back on the jet mean a broken pipe?

A sealed pipe is watertight. Sand and fine dirt are in the ground around the pipe, not inside it. If sand is coming back when you jet, the only way for it to get in is through a break or crack in the pipe wall. Always a reliable diagnostic for a broken line.

Why do old inspection openings have missing screws?

Standard practice until the 1980s was a screw-on cast iron cap on sewer inspection openings. Over decades, the screws corrode, get painted over, or get lost during garden work. Any old property we visit, the first thing we check is whether the IO caps are even still there, because missing caps let gases out and ground in.

Can I just keep jetting it until I can afford the repair?

You can, but each jet clear costs about the same and comes back sooner each time. Over a 2-3 year horizon, it is almost always cheaper to repair once than to keep jetting. The exception is if the property is scheduled for sale within 12 months, in which case the repair is a buyer problem.

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