Drainage guides / Practical advice
What should you check about drainage before buying a house?
Buried drains are easy to overlook during a property viewing. A few questions and a focused inspection can help you understand what is known before buying.
Start with the property’s drainage history
Ask whether there have been blockages, overflows, root problems or previous drainage work. Request available plans, inspection footage and records. A history of repeated clearing is a reason to ask what caused the problem and whether it has been investigated.
Records can provide context, but old footage describes the line at the time it was taken. Consider whether a current inspection is appropriate for the property and the information you need.
Confirm what your other inspections include
Do not assume that a general building inspection includes an internal camera inspection of sewer and stormwater drains. Ask each provider to explain their scope. A dedicated drainage inspection can complement the wider property checks rather than replace them.
If the property has an on-site wastewater treatment or septic system, ask what specialist assessment is required. An inspection of accessible pipes should not be treated as confirmation of the entire treatment system’s condition or suitability.
Agree a focused camera inspection
Tell the provider the property address, deadline and systems you want considered. Ask which access points are needed and what outputs can be supplied. If your adviser needs written findings or footage, arrange that before the visit.
The vendor or agent needs to authorise access. Sharing available drainage plans and known inspection-point locations can help the team understand the intended scope. Contact the provider early so there is time to discuss access and scheduling.
Review the findings and limitations
A CCTV inspection can show visible obstructions and condition issues in the sections reached. Bends, standing water, debris and blocked lines may prevent a complete view. Ask which sections were inspected, which could not be reached and why.
A clear-looking section does not guarantee the entire drainage system is fault-free. Consider the inspection’s limitations alongside the findings and seek further advice where a significant question remains unanswered.
If an issue is observed, ask where it is, what evidence supports the finding and what further assessment may help. Share the information with the professionals advising on your purchase. Avoid treating a single observation as a complete repair specification or a prediction of future costs.
Drain Kings offers pre-purchase sewer and stormwater inspections in Palmerston North and Manawatū. Discuss the property, your deadline and the information you need before arranging a visit. The purpose is a better-informed decision, with the scope and limits understood.
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