You can now get the latest water level alert of rivers all over Malaysia on covid19.place.
Originally a repository for detailed Covid-19 data from all over the world, similar to Covidnow, the page now shares a table of water level thresholds from rivers all over Malaysia.
The table is updated regularly using data from the Department of Irrigation and Drainage.

The river water level is expressed in four self-explaining categories: Normal, Alert Warning, and Danger.
Although convenient, the data presented is meant to be analysed and not to be taken as is.
For example, it would be more useful to know if the river is getting deeper compared to how deep it currently is.
So if you are using this site to monitor the flood situation in your area, you’ll have to refresh it regularly and keep an eye on the changing water levels.