Water on front passenger side floor 2005 subaru Outback with sunroof. Where are down hill drain ends located?

there should be drain holes that lets the water drain out check for them their most likely clogged

loose bolts somewhere in the front end? you have had lots of work done there. wheel weights can fall off or a rim can be difficult to balance?

the A/C drain is plugged you need to jack the car up the drain is on the passenger side you can try blowing air in it

Most likely the sunroof drains are clogged. It happened to mine, the floormats and floors were soaked, especially behind the drivers side. Volvo wanted to charge me $550 to clear them out and dry out the floors. Instead I took it home, rolled down the windows, parked it in the sun and let it dry out. Then I found a mechanic who blew out the drains with compressed air for only $20. He had originally quoted me $50-100, but ended up doing it for less. He said the two back drains are clogged. You can try sticking a small flexible wire down the front two yourself, then pour water down to see if it drains properly out the bottom of the car. When I looked I didn't see the two back sunroof drains, but my mechanic said they were clogged with leaves, you might be able to clear these yourself too. I would have never guessed that it was the sunroof causing this, because you don't see the water leak around the sunroof, you only see the water backing up on the floor. Don't take it to the dealership, it's a simple job and they will rip you off.

The most common source of water on the floor is a plugged a/c evaporator case drain hose. This drain is generally located down low on the engine side of the firewall at the passenger side and is usually a small short open ended hose that points down. Debris and bugs will clog this hose which makes the water that condenses on the evaporator [whenever the a/c is on] overflow and leak out of the heater/air conditioning housing and onto the floor. If it hasn't rained for some time yet you are still getting water on the floor I would bet on this hose being plugged. A puff of compressed air is enough to clean most of them out. Most sunroofs have one or two small drain holes that allow water to run down through the door pillars and onto the ground. If you pour a small amount of water around the top edges of the sunroof when it is closed you should soon see water dripping onto the ground under the outer edge of the vehicle. A few sunroofs just rely on tight weather stripping to keep the water out but those usually drip water on the driver or passenger if they are leaking. I see a lot of leaky windshields but again, it has to be raining for water to get on the floor from them.

Check the seal around your interior air filter. The seal can come off at one corner and allow water to run down the firewall and into the passenger side.

all sunroofs have drain pipes, usualy 4, one on each corner, they usualy run down the A pillars at the front and poke out near the kick panals by the footwell. the rears often run down the C pillar to the vicinity of the boot.
open the sunroof up and carefully pour lots of water around the drain gulley of the sunroof, you should see it pissing out onto the floor at the front and rear on each side. make sure water goes down all 4 corners of the sunroof and check. Pipes can come of at the roof. also the drain grommets block up.

common problem on passats also is the pollen filter housing letting in water (under the scuttle panel beneath the bonnet. on left hand drives though, this fills the passenger side only (left). not sure on RHD which side pollen filter housing is on , but when they leak the water fills up inside the car on one side only, which can flow front or rear depending on car being parked up or down hill.
the seal between the pollen filter housing and the bulkhead often leak, if you press down on the plastic housing you may hear the seal squelching water. there was a recall on this, so it may have been done.
If the comparment under the panel (where the battery is) is filling with water, there is a drain grommet under the batter that also blocks up sometimes, causing it to fill up and flow in where it shouldnt.

most common problem is the a/c condensor tube is clogged and is under the car and needs to be cleared with compressed air. also the sunroof track has 4 drain tubes and the right front may be clogged or leaking. you can check that by pouring a cup of water down the right front drain tube in the sunroof track and see if water comes out by the right front wheel

Is it possible the water is actually coming from the A/C evaporator case, whose DRAIN IS CLOGGED ? The water produced by the A/C then leaks out of the case, down under the carpeting, then depending how vehicle is parked, can flow to the rear floors and carpet. Hope this helps

check the sunroof drains,they may be clogged they are located on the right and left front of the sunroof.