Why I Won't Buy a Low-Lying House Without Crawling Under It First

I watched a video the other day. A homeowner in Melbourne — young bloke, decent house — filming water pouring through his living room ceiling. Not a drip. A waterfall. The gutter had blocked, the water had nowhere to go, and because his property sat lower than the neighbours on both sides, the entire street's runoff had funnelled straight into his roof cavity.

His first mistake wasn't the blocked gutter. His first mistake was buying a low-lying property without understanding what that means for water management.

Let me be clear: low-set houses aren't automatically bad investments. Some buyers — particularly older Australians — actually prefer them for the privacy. Trees screen the house from the street. The backyard feels enclosed and sheltered. If you're owner-occupying and you like that vibe, fine.

But if you're investing, you need to understand the risks. Because water damage is one of the most expensive problems a landlord can face, and low-lying properties are disproportionately exposed to it.

Where this matters most in Melbourne

Melbourne's eastern suburbs — Doncaster, Doncaster East, Templestowe, Templestowe Lower, Bulleen — sit on undulating terrain with significant elevation changes within individual streets. A property at the high point of a street might sit 3-5 metres above a property at the low point, just 200 metres away 1.

In these suburbs, the low-lying properties are the ones most exposed to overland water flow during heavy rain events. Melbourne's east gets approximately 650-700mm of annual rainfall, and climate data shows increasing intensity of individual storm events — less total rain, but more of it falling in short, heavy bursts 2.

When a 30mm-in-one-hour storm hits, the water flows downhill. It follows the natural contour of the land, and it pools at the low points. If your property is at a low point, your yard becomes a temporary detention basin whether you planned for it or not.

The planning system nominally addresses this through Special Building Overlays (SBO) and Land Subject to Inundation Overlays (LSIO). But these overlays don't catch every low-lying property. Many houses that sit below street grade or below their neighbours aren't in any overlay zone — they're simply topographically disadvantaged 3.

Our scouts Steven and Edward check topography on every property we inspect. They literally stand on the footpath and look at whether the house sits above or below the street surface. If it's below, the property gets flagged for deeper investigation — not automatic rejection, but deeper investigation.

What to check when you inspect a low-lying property

If you're looking at a property that sits below the street or below its neighbours, here's the inspection protocol I'd recommend — and what our team does every time.

Get under the house. This is non-negotiable. A qualified building inspector should crawl under the subfloor and check for:

• Moisture in the soil. Dry, compacted soil is good. Damp, soft, or muddy soil indicates ongoing water intrusion.
• Standing water or water stains on subfloor bearers and joists. Any evidence of pooling means the site is regularly inundated.
• Mould or fungal growth on structural timbers. This indicates prolonged moisture exposure.
• Termite activity. Subterranean termites thrive in moist soil. A damp subfloor is an open invitation [4].

Check the gutters and downpipes. Low-lying properties collect more leaf litter from surrounding trees (because the canopy above sheds directly onto the roof). Blocked gutters on a low-set house are catastrophic — there's nowhere for the water to overflow except into the roof cavity or down the exterior walls.

The fix is straightforward but requires ongoing maintenance: gutter guards (mesh covers that prevent leaf buildup) and a twice-yearly gutter clean. Budget $300-$500 per clean, or $800-$1,200 for gutter guard installation. It's cheap insurance against a $15,000 water damage repair 5.

Check the stormwater drainage. Where do the downpipes discharge? They should connect to the council stormwater system via underground pipes. If they discharge onto the surface (splash blocks or just dumping onto the ground), the water has nowhere to go on a low-set block — it pools around the foundations.

Walk the perimeter after rain. If possible, inspect the property within 24 hours of heavy rain. Look for ponding (standing water in the yard), water marks on fences, erosion channels in garden beds, and damp patches on exterior walls at ground level. These are the telltale signs of a property that regularly gets wet 6.

The financial impact of water problems

Let me put some numbers on this, because "water damage" sounds abstract until you see the repair bills.

A moderate water ingress event — where stormwater enters the subfloor and saturates the bearers — typically costs $8,000-$15,000 to remediate. That includes subfloor drainage installation, damaged timber replacement, mould treatment, and replastering of affected internal walls 7.

A severe event — where the property floods above floor level — can exceed $50,000. If carpet, cabinetry, electrical wiring, and plasterboard need full replacement, the costs escalate rapidly. Insurance may cover some of it, but flood exclusions are common in policies for properties in known low-lying areas 8.

And beyond the direct repair cost, there's the vacancy impact. A water-damaged property can't be tenanted until repairs are complete. If the remediation takes six to eight weeks (typical for a moderate event), you're losing six to eight weeks of rent — $5,000 to $7,000 at $850/week.

Total cost of one water event on a low-lying property: $13,000 to $22,000 for a moderate incident. That's two to three years of positive cash flow wiped out by a single heavy rainstorm.

This is why our due diligence process includes topographic assessment as a standard item. We don't automatically reject low-set properties — some of them are excellent investments with good drainage and no history of water issues. But we absolutely want to know what we're dealing with before we recommend a purchase 6.

When a low-lying property is actually a good buy

I said earlier that low-set properties aren't automatically bad. And I meant it. Some of the best-value properties we've purchased for clients have been low-set, because many buyers avoid them out of generalised fear.

A low-lying property is a good buy when:

• The subfloor inspection shows dry soil and no moisture history
• Stormwater drainage is properly connected to the council system
• The property has retaining walls and adequate site drainage directing water away from the building
• Gutters are in good condition (or you budget for gutter guards at purchase)
• There's no SBO or LSIO overlay on the title
• The vendor can demonstrate a history of no insurance claims for water damage

In our experience, about 60% of low-set properties in Melbourne's east are perfectly fine. The other 40% have issues ranging from minor (gutter maintenance needed) to serious (subfloor moisture requiring drainage works). The key is knowing which category you're looking at before you sign the contract 6.

We had one property in our portfolio that sat below the neighbours on three sides. On inspection, our scout found the previous owner had installed agricultural drainage (ag pipes) around the entire perimeter, connected to a sump pump that discharged into the council drain. The subfloor was bone dry. The drainage system worked perfectly. We bought it, rented it at $800/week, and it's been zero maintenance on the water front for three years.

Another property, two streets away, also sat low. No drainage system. Subfloor was damp, with visible mould on the bearers. We walked away. The buyer who purchased it spent $18,000 on remediation within the first year.

Same suburb. Same elevation profile. Completely different outcomes based on whether the previous owner had invested in proper drainage.

Do the inspection. Get under the house. Check the soil. That's how you separate the bargain from the money pit.

And for the love of all that's holy — if you buy a low-set property, clean your gutters. Twice a year. Every year. It's the single cheapest thing you can do to prevent the single most expensive problem.

I'm Yan Zhu. I check the gutters.