When it comes to, powder and liquid detergents aren't that different. Liquid detergent is better at greasy stains, while powder detergent is better at getting mud out.
The question is, though, which is better for washing your clothes and your washing machine?
Water temperature is a big factor. No matter if you choose cold, warm or hot, liquid detergent mixes with the wash water completely because it's already a liquid.
Some powder brands, on the other hand, don't dissolve as well in cold water settings, especially in high-efficiency washers. Since most of your clothes should be washed in cold water to prevent shrinkage and dyes from bleeding, this will quickly become a problem.
If the water temperature is under 68 degrees F (20 degrees C), you may find little clumps of leftover detergent on your clothes after a wash, requiring an extra spin cycle to remove them. This puts extra wear and tear on your washer and your clothes.
The health of your machine
Powder can also leave chunks of undissolved detergent in your washing machine parts. As you can imagine, this can lead to malfunctions. It particularly affects the washer's drainage system.
Over time, the clumps can build up, causing a blockage that looks a lot like hard water deposits. I had to call a repairman to fix my washer several times because it wouldn't drain. The repairman finally clued me in on his last visit -- my powdered detergent was doing the damage.
In addition to your washing machine, you may want to consider how your detergent affects your septic system, if you have one.
If you have an aerated system, it's best to choose a powder detergent that has a low level of surfactants, compounds that lower the surface tension of water. This will prevent bubbles from clogging the aeration chamber. If you have a gravity-powered septic system, though, liquid laundry detergents are a better choice.
Overall, look for detergents that are labeled as "Septic Safe."
: Here's what they really mean.
: Everyone should know about this.