If your favorite jeans come out of the washer with strange ripples, puckering, or wavy lines around the seams and thighs, the cause is usually changes in the fabric rather than permanent damage. Denim is often made from cotton, which can shrink when exposed to heat and moisture. When different areas shrink at different rates, especially around seams and reinforced sections, the fabric can buckle and create visible ripples.

Tension from manufacturing can also play a role. Jeans are stitched under varying levels of tension, and those stresses may become noticeable only after washing. Stretch denim can be particularly sensitive because elastane or spandex reacts differently from cotton. Repeated washing and drying may cause these fibers to lose their shape unevenly, resulting in twisting or warping.

Your washing routine can make the problem worse. Overloading the machine can cause jeans to twist, tangle, and become distorted, especially when heavier items are included. Rough cycles and high temperatures place additional stress on the fibers. High-heat drying is another common culprit because excessive heat can cause uneven shrinkage and make ripples more difficult to remove.

To help your jeans keep their shape, wash them in cold water and turn them inside out before putting them in the machine. Use a gentle cycle, avoid overcrowding the washer, and skip high-heat drying whenever possible. Air drying is gentler and can help denim retain its original shape while reducing the risk of new ripples and wrinkles.