water on rear passenger floor

Sounds like one of the door seals (rubber) is shot. Fairly normal, even in high end cars. Most body shops can help.

A good way to test this is to hose the side with the leak (with windows rolled all the way up and doors shut). Let it soak for a good 3 to 5 minutes, then check inside for where the water is.

Well that's what I thought too but the seat is dry the carpet by both door's is dry.I'll try what the other guy suggested,run water over the area and see where it comes in,I should have thought of that DA.Thank guys.

I just posted my first question here and saw your post. In my 99 Bonne one day after a weekend of heavy rain there was a puddle in the back rear floor where a person sitting in the back passenger's seat feet would be. Had no clue how it got there and why anything would puddle up there. It also stunk. I dried it out with a towel, blow-dried it and then used a heavy duty carpet cleaner to get the stink out. It has rained many times since then and it has never happened again, so if you get a reply that explains it let me know.

I have seen this before. If your car has a sunroof this will apply if not idk. There are four drainage hoses that run from each corner down each of the pillars. They can become disconnected, rotten or backed up. Any of these can cause a leak. I would check the one that corresponds to the corner the leak is at. This does require removing the headliner and rear seats but following the hoses should reveal the source of the leak, good luck

Well I don't know much, but it comes from the trunk. If you check the spare tire well is probably full of water and runs down under the passenger seat and onto the rear passenger floor. Not shure if it happens when you hit the brakes or just runs down the inner fender well and fills both. Have had 3 bonnevilles that have done the same thing. The 97 I had I tore the carpet and insulation all out and sealed some rust holes in the upper inner fender well area. I still think it comes from the trunk lid seal and usually during a freeze thaw cycle.

I have owned 2 ssei bonnevilles. Interior water is either sunroof drains (factory junk) or door seals pulling away from the pinch weld or under the cowl is an air intake for the heat/ ac system and the foam seal leaks. If sunroof replace drains with solid tubing. If door seals pull off and use drip check sealant in the groove that goes to the pinch weld. If the cowl intake use exterior sealant around perimeter of the intake. Good luck!

If your trunk leaks it is most probably either the tail lights or the back window seal on one of the lower edges. (Locked myself in the trunk with a partner on the outside with a hose. Ssei tail lights come un-laminated, water fills the light fixture with water and the when full enough it leaks in the trunk and fills the spare tire well. Might mess up you tail light bulbs too. If the rear window, replace the seal, if the tail lights remove, dry out, seal top edge with clear or black 3m 5200 sealant. Good luck!