Jeans can sometimes come out of the wash with strange ripples, puckering, or wavy lines, but that doesn’t necessarily mean they’re ruined. Cotton can shrink when exposed to water and heat, while seams, pockets, hems, and reinforced areas may react differently because they contain multiple layers of fabric and stitching. This can create tension that makes denim look uneven, especially around the side seams, thighs, knees, and waistband.

Heat is one of the biggest factors. Hot water and high dryer temperatures can encourage cotton to shrink and may also affect stretch fibers such as elastane. Over time, excessive heat can reduce elasticity and leave certain areas looking loose or wavy. Overloading the washing machine can make things worse because jeans can become twisted and compressed with other clothes. Strong agitation and high-speed spinning may also create deep folds.

The good news is that many ripples are temporary. After washing, shake the jeans out, straighten the legs, smooth the seams, and reshape the waistband before drying. Air drying is generally the gentlest option, while a low dryer setting is preferable if you need to use a machine. Gentle steam or careful ironing, if allowed by the care label, can also help relax minor puckering.

Ultimately, strange ripples usually come from the interaction of water, heat, stitching, fabric tension, and movement. To prevent them, wash jeans in cool or cold water when appropriate, turn them inside out, avoid overcrowding the washer, and limit high-temperature drying. If a new pair develops severe distortion after being washed according to its care instructions, the fabric or construction itself may be responsible.