Diagnosis
CCTV Drain Surveys Explained
What a drain camera can and cannot see, when a survey is worth paying for, and how to read the footage you're shown.
Buying
A pre-purchase CCTV drain inspection sends a camera through the property's private wastewater lateral before you buy, identifying root intrusion, cracks, displaced joints, dips and collapses. Standard building inspections in New Zealand generally do not include underground drainage, so these faults are invisible during a normal due diligence process. It is most worthwhile on properties built before about 1980, on sections with mature trees, and anywhere the vendor discloses a history of blockages.
A building inspection is a visual inspection of what can be seen. A good inspector will check the roof, subfloor, cladding, joinery, moisture readings and services — and will note if a gully trap looks poor or a fixture drains slowly on the day.
What they cannot do is see inside the drain. It is underground, it is enclosed, and inspecting it requires a camera, a locator and someone who knows how to read the footage. Most standard reports say so explicitly in their limitations section, which is worth reading rather than skimming.
So on a typical Auckland purchase you will get a detailed assessment of everything above ground and nothing at all about a lateral that may be a hundred years old, running under a driveway you are about to own.
A large proportion of Auckland's residential drainage is glazed earthenware or concrete laid in short jointed lengths before 1960, sitting in clay soils that move seasonally, under one of the more mature urban tree canopies in the country. That is close to a worst-case combination for drainage, and it is concentrated in exactly the older suburbs people most want to buy in.
Strong case:
Weaker case: a post-2000 build on a small section with no significant trees, where the drainage is almost certainly uPVC with sealed joints. Not impossible to have a problem, but the odds are much lower and the money may be better spent elsewhere.
| Finding | How serious | Typical remedy |
|---|---|---|
| Minor root hairs at one joint, no blockage history | Low — monitor | Often nothing immediately |
| Established root mass | Moderate — will recur | Cutting plus relining the affected section |
| Multiple open or displaced joints | Moderate to high | Full or partial lateral reline |
| Dip holding standing water | Moderate — chronic | Excavate and re-lay to correct fall — lining will not fix this |
| Cracked or fractured sections | High | Reline or excavate depending on extent |
| Partial or full collapse | High — urgent | Excavation and replacement |
| Stormwater cross-connected to wastewater | Moderate | Separate the connection correctly |
| Asbestos-cement pipework | Not a fault in itself | Nothing, but it changes how any future repair is handled and costed |
Two things worth holding onto. First, not every finding is a problem — a minor intrusion on a drain that has never blocked may be perfectly fine to leave. Anyone converting every observation into an urgent quote is not helping you. Second, the cost of the fix is driven mostly by depth and what sits on top, so the same fault under a lawn and under a concrete driveway are very different numbers. Our cost guide covers the ranges.
A drain report is unusually useful in a negotiation because it is specific, evidenced, and hard to argue with. You are not saying "the drains look old" — you are saying "there is root intrusion at 8.4 metres through a displaced joint, here is the footage, here is a quote to reline it."
Realistic options:
Either way you have removed a genuine unknown, and the footage stays useful after settlement as a baseline for the condition of what you have bought.
Practically, a drain inspection sits inside the same due diligence window as your building report — commonly under a building inspection or due diligence condition, or a specific drainage condition. It needs vendor consent for access and, ideally, water available at the property.
Two practical notes. It is far easier arranged alongside the building inspection than as a separate visit. And if the property is tenanted, access needs proper notice, so allow time.
At auction, where conditions are not available, the inspection has to happen before bidding — which means spending money on a property you may not win. That is genuinely annoying, and on an older property in a tree-lined street it is still usually the cheaper risk.
Almost never. Standard building inspections are visual and generally exclude underground drainage. Most reports state this in their limitations. If underground drainage matters to you, it has to be commissioned separately.
You can, and it is still useful as a baseline. What you lose is any leverage — once you own it, a collapsed lateral is entirely your cost. The value of doing it beforehand is almost all in the negotiating position.
Yes, for access. It is normally arranged through the agent alongside the building inspection. Vendors rarely refuse, and a refusal is itself informative.
Then it matters more, not less. On a shared private drain you may inherit a share of repair costs for a fault anywhere along the shared section, including on a neighbour's land. Knowing the condition, and where the shared portion runs, is worth establishing before you commit.
Usually not for age-related faults, though we do occasionally find construction debris left in lines and poorly bedded pipe that has deformed. If a builder's warranty is in place, that is generally the route to pursue.
There is no formal validity period. Drains change slowly — root intrusion takes years to develop — so a recent report is a fair representation. A report more than a couple of years old on a property with mature trees is worth refreshing.
Tell us what it is doing and we will tell you what it probably is, what it takes to fix, and what that should cost.