Big pool of water in 156 rear footwell

[Parabola]

Used my 03 156 SW for the first time in a few days yesterday.
Chucked my coat on the back seat, and noticed a huge puddle of water in the rear drivers side footwell. The floor mat was a couple cm underwater. I would guess 3 or 4 litres of water!

We did have heavy rain a couple of days ago, but I'm confused by how much water got in, and in such a localised place. The headlining/sunroof/door are all bone dry.
I'm pretty sure the door and electric window were shut properly.

Any ideas where the water could have got in.. and how I can prevent it happening again?

[Fulvisti]

Why yes! Have a look at this link. http://www.alfa156.net/fr_index.html?/info.html

See the water leakage link on the above page. Apparently it's not uncommon, hope this helps

[Oilchange]

ta for the heads-up, just silicon sprayed the entire door seal area (and black plastics). Will repel water and look shiny for a while...

[uncinquesei]

Had the same in my 156, o/s rear footwell swimming, it wasn't the door. The sunroof has four drains (one at each corner) that are connected to rubber pipes that exit near the wheelarches. They have non return valves at the ends and get blocked up with years of muck and stuff and there is a joint in the pipes in the C pillar (ie between rear door and rear screen). When the pipes are blocked the water backs up and leaks out of these joints, runs down the outside of the pipes - some enters the car by the rear seat base and some goes into the boot (my spare wheel well was filling up. I cut the valves off the ends of the rear ones on my car and released a pleasant cascade of old rainwater. Blasted the tubes out with an airline and have never looked back. The only consequence has been a slight gurgling/whistling noise from the tops of the tubes with the sunroof open in wet weather. I can live with it. I do occasionally blast the pipes out just to be on the safe side. Hope this helps.