Heavy rain can reveal drainage weaknesses quickly. A few observations before the next wet period can make the problem easier to explain.

Walk the property after rain

Look for pooling, erosion, overflow, water moving toward the building and downpipes that are not carrying water away.

Separate stormwater from plumbing

Surface runoff and roof drainage are different from wastewater plumbing. Identifying which system is involved helps direct the investigation.

If an area repeatedly floods or a drain overflows, arrange an assessment before the next prolonged period of rain.