Is he far from his litter box? Sometimes they want it changed to a different spot in the cage, so they go there until you move the litter pan "under them" so to speak. Try moving the litter pan over just a bit and see if that's easier for him to get to it.

If not, keep an eye on him to try to see if he's peeing because he can't control it. If he's drinking more he just has to pee more, but it could be an indication that there's a physical problem brewing. See if it continues or worsens, and if so, call your vet.

How many pellets does he get in his diet? I know with Rufus he gets alot more pellets then the other rabbits as he does not eat hay (we are working on that) and the vet said that pellets have a higher salt level and increase drinking and peeing. Also if he is an older rabbit he might have some issues with his Kidneys, next vet visit get them to check I did and discovered Rufus kidneys function is high which is not great but could also explain extra pee

Also, his litterbox is in the corner, not very far from the middle. Though he pees in the box so much all the bedding is soaked. Maybe he doesn't like soaked bedding.

Bun-Bun started drinking and peeing way more when I brought him home, but I started giving him more fresh veggies and fewer pellets. He was just at the vet to get neutered, and the vet said that drinking and peeing a lot is good, when they eat a lot of roughage like hay and veggies, they need to drink more water to help digest everything. I've seen other threads here that mention rabbits drinking quite a bit of water.

Peeing out of the box is annoying, mine does that occasionally (but happily not on the carpeted levels of his cage which would be harder to clean.) Usually just outside of the box on the tiled floor of his cage, or on my hardwood floor outside the cage (but near the litter box side, he may just be confused?) Since he just got fixed yesterday I have to wait and see if this pee situation gets a little better.

It could be due to the soaked bedding. They usually don't like it, and I know my bunnies have occasionally peed outside the box as a message to get it cleaned before they would use it again. So I did, and they would. which reminds me....

Try changing it more frequently, or using a more absorbant litter. I also drop a handful of Aspen shavings across the top in the morning if I have to get to work and don't have time to clean it out until I get home. (today)

Definitely change the litter more often, if it is getting that soaked. Mine don't like soaked litter either.

Okay, I'll change it more often. But is it bad if he suddenly started drinking more two days ago?

Its possible something is wrong, just keep an eye on him. If it gets worse, or doesn't go back to normal, I'd take him in just in case.

Sometime they self regulate their water intake. It could be because the hay is different, sometimes they can soothe a sore mouth by drinking, sometimes because they're bored or they just find it fun to drink. Sometimes due to environment temp change. I think also when they have a slight infection too. Lots of various reasons but the main thing is go to the vet if it continues to be excessive and out of character for him. And watch for other signs of health issues.

Okay, I will monitor him and see. It looks like he's not drinking quite as much today, so maybe he felt hot or something yesterday. Thanks for all of your replies!