I have the same issue. What did you do to resolve it? Replace reservoir?

Read the thread. It is usually the pumps where they are installed in the reservoir. There is a grommet there. Easy to diagnose.

sometimes the one of the washer pumps develops a leak, sometimes it's the grommets.

agreed check those rubber seals around those 2 black pumps or sometimes where the sensor is has a leak too...

Verified my Reservoir didn't leak. Heated up my grommets. Snipped off the ends of the tubing on both pumps. Filled it back up with fluid. No leaks right now. Only time will tell. Will monitor it and report back.

Washer fluid is leaking out of my headlight washers

In my case the leak was from the washer pump itself. I replaced with a new one for $42 from http://thebmwminipartstore.com/. The old one was all rusty inside.

Parts View
 

Washer Pumps parts exploded view
If you have blue colored stains near a pump, line, connector, bucket---YOU HAVE/had LEAKS.

The X5 with only winshield washers have just one pump. If you have front and rear washers, and headlamps you have two little pumps and the big one is the headlamp washer. This is such a common failure that everyone makes the replacement pumps. Search any vendor and compare before buying OE.

If you have not removed this bucket, I would recommend removing the whole assembly, after disconnecting the hose lines and electrical connections, washing the bucket out with some a weak solution of Clorox (1/2 cup per gal) to remove any dirt and mold build up.

The pumps should ALWAYS be replaced with the seals (screens) #3 & 12.
Lines leak, right angle plastic connectors crack, pumps fail (some even even leak with no pressure others spray everywhere when turned on). After 10+ years just replace them. Those who's X5 were not well respected by former owners might want to see if the bucket itself is cracked due to plain water being used in winter months. Beats having to mop up "blue fluid" on the garage floor weekly.:thumbup:

Carefull of using compressed air to "clean lines" as the rear washer lines will pop off giving you a leak in to the battery well. Not a good thing, as all the electronics are down there too!

As mentioned before, this repair is easy. Two nuts holding down the bucket, a few electrical connectors, and a hose or two or three depending on your X.

Image from Penske Parts - Technical Diagrams & Parts Catalog
http://www.penskeparts.com/DiagramsM...png?v=03192010

#Part Number DescriptionlbQtyhttp://www.penskeparts.com/images/infoheader.gifEach
01 61667007880 COVER F WINDSHIELD CLEANING CONTAINER (to 09/06)0.02 1 NAhttp://www.penskeparts.com/images/infoheader.gif 61667007880 was superseded by 61667228601.
01 61667228601 COVER F WINDSHIELD CLEANING CONTAINER0.02 1 NAhttp://www.penskeparts.com/images/infoheader.gif 61667228601 was superseded by 61667264145.
01 61667264145 COVER F WINDSHIELD CLEANING CONTAINER0.02 1 $4.12
02 61678252738 HEAD LAMP CLEANING DEVICE CONTAINER1.24 1 $188.29
03 61667006063 STRAINER F WASH PUMP 2 $2.80
04 67128362154 WASH PUMP0.22 2 $62.54
05 61661365848 STRAINER F WATER CONTAINER (to 09/00) 1 $3.95
06 17137524812 LEVELLING SWITCH0.02 1 $18.80
17137524812 was superseded by 17137553919.
07 16131176747 PLASTIC NUT - M6 2 $0.50
08 61688252747 CONNECTION PIECE 1 $3.78
09 61668362762 HOSE LINE (meter)0.09 1 $7.17
10 61668374371 SUPPORT 1 $3.47
11 67128377430 WASH PUMPE F HEAD LAMP CLEANING DEVICE0.37 1 $93.82
12 61678374382 STRAINER F WASH PUMP0.02 1 $4.87
13 61138364520 UNIVERSAL SOCKET HOUSING UNCODED - 2 POL.0.01 2 $1.63
61130009633 DOUBLE FLAT SPRING CONTACT, MDK3 W. WIRE - 0,5-1,0 MM²0.01 4 $3.03
14 61138365340 UNIVERSAL SOCKET HOUSING UNCODED - 2 POL. 1 $3.27-- 61130005199 BUSHING CONTACT - 0,2- 0,5MM²0.01 2 $2.75

Makes sense. One of my pumps seem to have a rust spot in and around some drain hole looking thing on the pump itself. I believe it's my rear pump. If it leaks again, I may repair of just block the hole on the reservoir.

Dam I only paid $6 for mine