Literally: day/sun – usual – tea – (cooked) rice
Alternately: An everyday occurrence. Just as boiled rice is a stereotypical part of almost every meal in Japan – breakfast, lunch, and dinner, every single day – and tea is a super common drink, so is the event described with this phrase utterly unremarkable in its universality. For a given cultural or personal context, at least.
Notes: Keep in mind that the “tea” here is pronounced sa rather than the more common cha. Also, despite this being a “four-character idiomatic compound,” feel free to add 事 (ji) to the end to express… exactly the same concept. Isn’t Japanese fun?