aiyah while wait for the rains drop why not try to spray water and test first ......u're is leaking problems not water splashing problem mah, right?

try to block the water outflow hole and let the water cover the whole concrete slabs that u wanted to test at least half an inch high then u leave it for half an hour if leak u will already know immediately why wait? but pls ensure the water is not drain out to have a accurate results ...... this method is the fastest way ...... just sharing .....