5 Signs of Rodent Infestation Every HDB Homeowner Should Know

You have not seen a rat. But something has been at the bread bag. There are small dark specks near the back of the kitchen cabinet. You tell yourself it is probably nothing.

It is probably not nothing.

Rodent infestations in HDB flats are more common than most residents admit. Singapore's tropical climate, dense buildings, and shared infrastructure give mice and rats easy access to homes year-round. The key to avoiding serious damage and health risks is recognising the signs early — before a small problem becomes an established colony.

Here are 5 signs of a rodent infestation that every HDB homeowner should know.

1. Droppings Near Food Storage and Cabinets

Dark, pellet-shaped droppings are the most reliable indicator of rodent activity. Mouse droppings are small and pointed at both ends — similar in size to a grain of rice. Rat droppings are larger and capsule-shaped.

Check the inside corners of lower kitchen cabinets, behind the refrigerator, and under the sink. Fresh droppings are dark and moist. Old ones turn grey and crumble easily. More droppings mean a larger population.

2. Gnaw Marks on Food Packaging, Wiring, and Furniture

Rodents gnaw continuously — not because they are hungry, but because their front teeth never stop growing. Common gnaw targets include plastic food packaging, electrical cables, wooden cabinet bases, and rubber seals around pipes.

Gnawed wiring is particularly dangerous. It is one of the leading causes of unexplained electrical faults and house fires in residential properties. If you find bite marks on cables anywhere in the flat, treat it as an urgent warning sign.

3. Scratching or Scurrying Sounds in the Ceiling at Night

Roof rats

• the species most commonly found in Singapore HDB ceiling voids — are nocturnal. The hour after lights out is typically when activity peaks.

If you hear scratching, scurrying, or light thumping sounds from the ceiling or inside walls after dark, there is almost certainly a roof rat using the space above as a runway or nesting site. One ceiling void can connect to multiple units via pipe runs and unsealed junctions, so what starts in one flat can spread quickly.

4. Grease Marks Along Walls and Skirting Boards

Rodents are creatures of habit. They travel the same paths repeatedly, pressing their fur against walls and skirting boards for guidance in the dark. Over time, this deposits a dark, oily smear at a consistent height.

Look for grease marks along the base of walls in less-trafficked areas — behind appliances, along service pipes, or near the back of cabinets. Fresh marks are glossy. Older marks are dull and darker. A clear grease trail indicates an active, frequently used runway.

5. Nesting Materials in Concealed Areas

Rodents build nests using whatever soft material is available: shredded paper, fabric, cotton, plastic packaging, and insulation foam. Nests are always built in dark, undisturbed locations.

Common nesting sites in HDB flats include the space inside false ceilings, behind built-in wardrobes, inside stored cardboard boxes, inside the cavity beneath the kitchen sink, and inside appliances that generate heat such as the back of the refrigerator or the underside of the oven.

Finding a nest means a female has already given birth or is about to. Rats can produce 5–7 litters per year. Acting immediately limits the population before it multiplies further.

What to Do If You Notice These Signs

Do not use supermarket poison blocks placed randomly on the floor. Rodents are neophobic — they avoid unfamiliar objects for days and may never approach incorrectly placed bait. Ultrasonic repellers have no proven effect on established populations.

The most effective step is to contact professional rodent control in Singapore as early as possible. A licensed technician can confirm the species, locate the nesting site and entry points, apply targeted baiting at the right locations, and seal the gaps preventing reinfestation.

In HDB properties, early treatment also prevents the infestation from spreading to neighbouring units via shared ceiling spaces and drainage runs.

One Final Note

There is rarely just one rodent. A single sighting, a single dropping, or a single sound is almost always evidence of more. The longer an infestation goes untreated, the more difficult and costly it becomes to eliminate. Act on the first sign.

Uneeb Khan is the founder of Techager and has over 6 years of experience in tech writing and troubleshooting. He loves converting complex technical topics into guides that everyone can understand.