How to Properly Clean Grout

Grout is the material that fills the gaps or 'joints' between tiles. It prevents debris from seeping into hard-to-reach spaces and adds structural support to tile surfaces. Grout also seals areas around countertops, backsplashes, bathtubs, and floors, all while contributing to the aesthetic appeal of the surface it's applied to. Over time, everything collects dirt, and the question becomes: how do you clean grout effectively?

When dealing with stained grout, here’s the harsh reality: unlike tile, grout can be tough to clean. If you approach this task the wrong way or use a too-powerful cleaning solution, you risk damaging the grout and potentially facing costly repairs.

To make matters worse, many common household cleaning products fail to do the job. These products might make other surfaces gleam, but they won't tackle the stubborn grime that’s become embedded in the grout’s seams.

So, how can you maintain clean grout? We’ve done the research, and now it’s time to reveal the best solutions.

Start by Understanding Your Grout

While tiles themselves are generally resistant to stains, the type of grout used between them plays a significant role in how easily it can stain. There are three main grout types: sanded grout, unsanded grout, and epoxy grout.

Sanded grout and unsanded grout (also called cementitious grout) both have a cement base, but unsanded grout is smoother, as it contains finer sand particles. Sanded grout is ideal for tile joints one-eighth inch (0.3175 cm) wide or more, like those on floors, whereas unsanded grout is suited for narrower gaps, such as those on shower or backsplash tiles. Both types of cementitious grout must be sealed with a waterproofing sealer during installation and resealed every few years to maintain maximum stain resistance.

Epoxy grout is a blend of epoxy resin, silica fillers, pigments, and a hardening agent. It is available in both sanded and unsanded variations. Epoxy grout doesn’t require sealing, making it more resistant to stains compared to other types.

Unfortunately, the reality is that all grout—whether cement-based or epoxy—can stain over time.

Choose a Cleaner With a Balanced pH

A good approach to grout cleaning is "first, do no harm." Cleaning products, even those made from scratch at home, that contain strong acidic or alkaline substances can break down the sealant protecting the grout from stains. Once the seal is compromised, harsh cleaners can begin to erode the grout itself.

The pH scale runs from 0 to 14, with acidic liquids scoring lower and alkaline liquids scoring higher. The midpoint, or neutral pH, is 7. For instance, lemon juice and vinegar are both highly acidic, with a pH of 2, while chlorine bleach is highly alkaline with a pH of 12.

In general, acid-based cleaners work well for shining metal fixtures or tackling hard water stains. Alkaline-based cleaners are better suited for cutting through grease or removing built-up grime. However, when it comes to grout cleaning, it’s best to start with a gentle solution that’s balanced in the pH range.

Steps for Tackling Grout Stains

Here are the steps you can follow, from the easiest to the most intense, to clean your grout effectively:

1. Begin with water

The gentlest cleaning solution is simply water. Start by spraying the grout lines with warm water, ensuring that the grout is damp, not drenched. Use a nylon brush with soft to medium bristles to scrub the grout in a circular motion. After you’ve scrubbed thoroughly, wipe the grout dry. You don’t want it to stay damp, as this could lead to mildew growth.

2. Boost the cleaning power with vinegar and water, but be cautious

If the grout still appears stained, you can increase the acidity of your cleaning solution by using a vinegar and water mixture in a spray bottle. However, be aware of the potential risks. If the grout is unsealed or hasn’t been resealed recently, avoid using even a diluted vinegar solution on the stains.

Vinegar’s acidity can damage the grout. Even sealed grout is at risk when cleaning with vinegar-based solutions. The same applies to solutions containing lemon or other low pH liquids, as well as those with bleach or ammonia that have a high pH. These substances can harm grout.

If the risk of damaging the sealant or grout is acceptable to tackle a stain, then a one-time use of vinegar may be justified. However, many grout and tile specialists warn against using vinegar on floors or grout. If you choose to proceed, some experts recommend a mixture of vinegar and warm water in equal parts, which can be sprayed on sealed grout and scrubbed with a brush.

3. Consider a baking soda paste

If this solution doesn’t remove the stains, cover the grout lines with a baking soda/water paste and then spray with a diluted vinegar/water mixture, followed by scrubbing. If the grout is unsealed, apply the baking soda/water paste alone without the vinegar spray. Scrub and wipe dry.

4. Try a baking soda/hydrogen peroxide paste

For particularly tough stains, whether sealed or unsealed, a baking soda/hydrogen peroxide paste can be effective. Apply the homemade paste, lightly scrub, let it sit for a few minutes, then rinse and wipe dry.

5. The final option: Commercial stain remover

For grout that remains deeply stained, especially with mold or mildew, you may need to turn to an over-the-counter commercial stain remover for help.

6. Steam cleaning is another viable choice

If you're hesitant about using acid- or alkaline-based cleaners that might cause damage to grout over time, steam cleaning could be the ideal solution. A steam cleaner is a device that heats water to over 200 degrees Fahrenheit (93 degrees Celsius) and uses attachments like nozzles or brushes to direct the steam to specific areas, such as grout lines. Since it relies on superheated water to lift and remove stains, there's no concern of the damage that can be caused by acidic or alkaline cleaning solutions.