Cold-water washing has become very popular in recent years. It saves energy, protects some fabrics, and is often advertised as “gentler” on clothes. While that’s true for certain items, cold water is not a universal solution. In fact, using it on the wrong things can lead to lingering bacteria, bad odors, fabric damage, or clothes that never truly get clean.

Many people assume that detergent alone is enough to do the job, regardless of water temperature. But for some items, heat plays a critical role in breaking down oils, killing germs, and removing deep-set grime.

Here are 7 items you should never wash in cold water—and exactly why warm or hot water is the better choice.

1. Towels

Towels may look clean, but they are one of the dirtiest items in your home.

They absorb moisture, dead skin cells, sweat, and bacteria every time you use them. Cold water simply isn’t strong enough to remove all that buildup or kill odor-causing microbes.

Why cold water fails:

Cold water struggles to dissolve body oils and detergents fully, leaving residue trapped in the fabric fibers.

What to do instead:

Wash towels in warm or hot water (40–60°C / 104–140°F) to properly sanitize them and restore softness.

2. Bed Sheets and Pillowcases

You spend hours every night shedding skin cells, sweat, oils, and sometimes saliva onto your sheets.

Cold water may remove surface dirt, but it often leaves behind oils that attract dust mites and bacteria.

Why cold water fails:

Oils from skin and hair don’t break down well in cold temperatures, leading to lingering odors and allergens.

What to do instead:

Use warm water for regular washes and hot water if someone is sick or has allergies.

3. Underwear

This one is non-negotiable.

Underwear comes into direct contact with sweat, bacteria, and bodily fluids. Washing it in cold water increases the risk of bacteria surviving the cycle.

Why cold water fails:

It doesn’t effectively kill germs like E. coli or yeast that may linger in fabric.

What to do instead:

Wash underwear in warm or hot water, depending on fabric care labels, to ensure proper hygiene.

4. Socks

Socks absorb sweat all day long and often carry odor-causing bacteria and fungi.

If you’ve ever washed socks in cold water only to find they still smell “off,” you already know the problem.

Why cold water fails:

Cold temperatures don’t fully remove sweat oils or kill odor-causing microbes.

What to do instead:

Use warm water and make sure socks are completely dry after washing to prevent bacterial growth.

5. Kitchen Towels and Sponges (Yes, Cloth Sponges Too)

Kitchen towels are exposed to food residue, grease, and bacteria like salmonella and E. coli.

Cold water may rinse them, but it won’t sanitize them.

Why cold water fails:

Grease and food oils harden in cold temperatures, making them harder to remove.

What to do instead:

Wash kitchen towels in hot water and replace them frequently.

6. Heavily Soiled Clothes

Workout clothes, gardening clothes, or anything stained with mud, grease, or body odor needs more than a cold rinse.

Why cold water fails:

Cold water locks in certain stains—especially oil-based ones—making them harder to remove later.

What to do instead:

Use warm water for most stains and pre-treat heavily soiled areas before washing.

7. Reusable Cleaning Cloths and Mop Pads

These items are designed to collect dirt, bacteria, and cleaning chemicals.

Washing them in cold water defeats their entire purpose.

Why cold water fails:

It doesn’t remove bacteria or chemical residue effectively, allowing germs to spread the next time you use them.

What to do instead:

Wash in hot water and allow them to dry completely before reuse.