You should wash your mattress protector once per month. You may want to wash it more frequently if you sweat a lot, have a dust allergy or asthma, or if you allow your pets to sleep on the bed with you., In general, you should wash your mattress protector every one to two months, though when to wash depends on what your mattress protector comes in contact with. Wash your mattress protector as soon as possible after a spill or accident., How Often to Wash a Mattress Protector . A mattress protector covered by the bottom sheet only needs washing once a month. Allergy sufferers will find it helpful to wash the mattress protector every two weeks, and the protector should be washed more often if someone has a cold or viral illness., Ideally, wash your mattress protector every two to four weeks to prevent dirt build-up and allergic reactions. It can be tricky enough to sleep during a bout of flu or a cold, so you likely won’t have the energy to do loads of laundry., Now that you have a good idea of how often you should wash your mattress protector, let’s get into the process. Fortunately, it’s just as easy as keeping your linens clean, though you should look at the specific care instructions for your model., According to Tom Ceconi, president of Heritage Park Laundry Essentials, this means washing your mattress protector every one to two months under normal usage. However, he adds that ‘this can vary based on individual sleep habits and environmental factors..