Bundesmann Testing (ISO 9865) demonstrates washing does not deteriorate water repellency performance.

Bundesmann water repellency is estimated to be 200-1000x more severe than an AATCC 22 spray test. In addition, Bundesmann testing uses metal rotors that rub against the fabric during the water test, so abrasion resistance is also a component of the test.  

Some performance brands compare the Bundesmann test results before washing and after 3 wash/dry laundry cycles. The video below shows the water repellency of a thin polyester fabric after 3 wash/dry cycles and compares those test results to the same fabric and treatment before washing. No difference is seen after washing compared to before washing and both results show outstanding performance even under the grueling conditions of the Bundesmann Test. 

These test conditions used high pressure, dry curing (HP = 10 Bar), Pod = 30 Bar, TC = 1 Bar.

Video Proof of Laundry Durability

Here is proof of laundry durability.  We compare the same fabric having the GTT treatment and a C6 and C8 padded treatment by a major apparel brand after a number of wash/dry cycles that were done in the same home laundry system. 

HD Video of direct comparison of GTT Evergreen finish (dry), C8 wet finish and C6 wet finish, all on the same polyester fleece fabric. GTT finish has been washed/dried 75 times, C8 finish has been washed/dried 50 times, C6 finish has been washed/dried 40 times. This video is 1 min 14 sec.

Quantitative Wash/Dry Comparative Test Data

C8-Treated Fleece, C6-Treated Fleece, GTT dry treated Fleece

In this data set, we compare the same fabric from a leading apparel brand treated using a C8 "wet" finish, and a C6 "wet" finish and the GTT fluorocarbon-free dry finish after a set number of wash/dry cycles.  The AATCC-22 spray test is used to compare the performance after the shown number of laundry cycles, plus the weight of absorbed water after a spray test is also shown in the right column.

Clearly, the GTT Evergreen™ finish has far better laundry durability than either fluorocarbon finish.  Please also see the laundry performance data shown below for 100 washes for a wide range of fabrics.