Fact: Septic systems rely on important bacteria to help break down waste, so if you’re putting any harsh chemicals into the system, it may harm the microorganisms and stop the system from functioning as efficiently.
When you have a septic system, you'll need to choose a laundry detergent that's labeled septic safe. It's also beneficial to choose a biodegradable detergent with low levels of surfactants. And if you have an aerated septic system, you'll probably want a high-efficiency or powdered laundry detergent to avoid excessive foam.
Knowing these things, we researched the best laundry detergents for septic systems, evaluating ingredient lists, effectiveness, value, and environmental impact.
ECOS Liquid Laundry Detergent with Built-In Fabric Softener
The ECOS Laundry Detergent is our top pick because it's biodegradable and safe to use in a variety of home water systems. We also love the light smell and effective cleaning power of its eco-friendly formula. This concentrated product comes in 100-ounce bottles that can be used for up to 100 loads of laundry, and its plant-powered formula has a wonderful magnolia and lily scent. Its formula is free from dyes, optical brighteners, parabens, phosphates, and phthalates, and it's hypoallergenic and pH-balanced for users with sensitive skin.
This laundry detergent also includes a built-in fabric softener to save you money, plus it works in all water temperatures and in both high-efficiency (HE) and standard washing machines. It's also certified as a U.S. EPA Safer Choice product, meaning it's made with ingredients that are safe for human health and the environment. ECOS is also a climate positive company, where all of their products are made in carbon neutral, water neutral, TRUE Platinum Zero Waste factories that use 100 percent renewable energy. So, you can not only feel good about using this detergent with a septic system, but you can also feel good about the impact your purchase makes on your personal and environmental health. How's that for a win-win?!
Overall, we think this detergent is not only a cost-efficient option, but it's also environmentally conscious and effective against tough stains and smells in your clothes.
Price at time of publish: $31/2-pack
Arm & Hammer Plus OxiClean Odor Blasters Laundry Detergent
Certain septic-safe detergents are quite expensive, but you can stick to your budget with the Arm & Hammer Plus OxiClean Odor Blasters Laundry Detergent. This popular household brand is specially formulated to break down body odors, sweat, and other tough scents, but its formula is still safe to use in your septic system.
This detergent comes in 122.5-ounce bottles that can be used for around 70 loads of laundry, and the formula is biodegradable, making it ideal for use in homes with septic systems. Arm & Hammer detergent contains OxiClean Stain Fighters that help to remove dirt and stains from clothing, and it’s a favorite among homeowners, thanks to its fresh smell and affordable price.
Price at time of publish: $10
Seventh Generation Free & Clear Concentrated Laundry Detergent
For a more eco-friendly detergent, you can’t go wrong with the Seventh Generation Free & Clear Unscented Concentrated Laundry Detergent. This top-rated formula comes in 40-ounce bottles that contain enough detergent for up to 53 loads or 100-ounce bottles that last for 66 loads, and as its name suggests, the detergent is hypoallergenic and fragrance-free, ensuring it doesn’t irritate sensitive skin.
What's so great about this product? Seventh Generation Detergent has a powerful triple-enzyme formula that effectively breaks down dirt and stains, and it’s actually both a USDA Certified Biobased Product and an EPA Safer Choice Certified Product. The cleaning solution is biodegradable and septic safe, and despite its gentle nature, we think a little bit of the plant-based formula goes a long way toward getting clothing clean.
Price at time of publish: $15
Method Free + Clear Laundry Detergent
If scented laundry detergents irritate your senses—or you just prefer not to have your clothes smelling floral—you’ll like the Method Free + Clear Laundry Detergent. This naturally derived formula is made without any dyes or fragrances, and it’s hypoallergenic, too, making it a great choice for anyone with sensitive skin.
Best of all, this high-efficiency detergent has no formaldehyde, parabens, chlorine, phosphates, phthalates, and DEA, yet it still removes dirt and stains, keeping colors bright and whites clear. The naturally derived detergent comes in 53.5-ounce bottles (made from recycled plastic), which you should be able to use for up to 66 loads of laundry. And, of course, the biodegradable formula is safe to use with septic systems, so you can rest easy knowing it won’t harm beneficial bacteria.
Price at time of publish: $15
Solimo Concentrated Liquid Laundry Detergent
Many laundry detergents are diluted with water, which means you have to use more product per cycle. But Solimo Concentrated Liquid Laundry Detergent is a septic-safe formula that hasn’t been watered down. In fact, you’ll be able to complete up to 128 loads of laundry using the affordable 96-ounce bottle.
This detergent is available in several scents, including lavender, clean linen, and unscented Free Clear. It’s compatible with both high-efficiency and standard washing machines, and the formula contains powerful stain fighters to leave your household's clothes squeaky clean after every wash! The concentrated detergent has twice as many loads per bottle versus a standard formula, and the brand even offers a money-back guarantee within a full year of purchase.
Price at time of publish: $18
Charlie's Soap Fragrance Free Laundry Powder
If you prefer powder laundry detergent to liquid products, one of the best septic-safe choices is Charlie’s Soap Laundry Powder. This eco-friendly formula comes in 2.64-pound bags that contain up to 100 loads of laundry.
Charlie’s Soap is made with powerful natural ingredients—in fact, there are just four ingredients used in the formula—and it’s biodegradable and free from artificial brighteners and perfumes. The powder detergent doesn’t create suds, making it better for aerated septic systems, yet it still effectively removes dirt, grease, and stains, leaving fabric fresh and soft.
Price at time of publish: $55
Dropps Stain and Odor Laundry Detergent Pods
Laundry detergent pods are undeniably convenient, as you can simply toss them into the washing machine—no measuring required. If you’re searching for a septic-safe laundry pod, you’ll definitely want to consider the Dropps Stain and Odor Laundry Detergent Pods, which are eco-friendly and incredibly effective.
These pods come in boxes of 140, and they’re available in several scents, including lavender eucalyptus and clean scent. The 4-in-1 plant-based formula includes a detergent, stain fighter, brightener, and odor defense, using essential oils and botanical extracts to leave your clothes smelling fresh. Despite their powerful cleaning abilities, these laundry pods are free of any dyes, chlorine, phosphates, enzymes, and optical brighteners, and they’re safe to use with septic systems and in all styles of washing machines.
If you like to prioritize eco-friendly products, you'll be happy to know Dropps ships its laundry pods in recyclable cardboard boxes, and all of its ingredients and packaging are sourced from suppliers that meet high-quality standards.
Price at time of publish: $47
While there are a few good detergents out there for septic systems, we've zeroed in on our top two picks. If you're looking for the best overall laundry detergent for septic systems, ECOS Liquid Laundry Detergent with Built-In Fabric Softener is compatible with all sorts of machines, gentle on sensitive skin, and biodegradable. Another good option is popular Arm & Hammer Plus OxiClean Odor Blasters Laundry Detergent, which comes in at a slightly lower price point. We love that it's a trusted brand and has powerful stain-fighting properties and a pleasant scent.
What to Look for in a Laundry Detergent for a Septic System
Septic Safe Label
When choosing a detergent that will work well for your septic system, be sure to look for labeling that indicates that the product is septic safe. A biodegradable detergent that has low levels of surfactants is ideal. Choose a powdered or high-efficiency laundry detergent that does not foam up too much if you have an aerated septic system.
Buying eco-friendly laundry detergent is one small thing we can all do to help protect the planet. Choose an eco-friendly detergent that is hypoallergenic, fragrance-free, biodegradable, and septic safe. That way you can keep yourself, your septic system, and the earth a little healthier and happier while you get your laundry clean. After much research, we've selected ECOS Liquid Laundry Detergent with Built-In Fabric Softener as our number one septic safe choice. It's biodegradable, compatible with many machines, and gentle on sensitive skin. Plus, we were happy to learn that ECOS is also a climate positive company. All of their products are made in carbon neutral, water neutral, and zero waste factories that use 100 percent renewable energy.
Using less detergent will help keep your septic system healthy. If you prefer liquid detergent to powder formulas, be sure to select concentrated formulas that will work hard with less product, meaning it'll last longer and keep your septic system happy. We think a great pick is Seventh Generation Free & Clear Unscented Concentrated Laundry Detergent. This concentrated formula comes in 40-ounce bottles that contain enough detergent for up to 53 loads. Plus, the detergent is hypoallergenic and fragrance-free, so it won’t irritate sensitive skin. Another smart option is Solimo Concentrated Liquid Laundry Detergent, a septic-safe formula that'll give you up to 128 loads of laundry with a 96-ounce bottle.
How does a septic system work?
A septic system is an underground treatment center for wastewater from your kitchen, laundry room, and bathroom. The wastewater drains into a central area where it separates oil and grease that floats to the top as scum, and solids that sink and form a sludge. Bacteria breaks down the waste and the remaining liquid drains into a drainfield where bacteria treat wastewater before it is safely released into the ground soil.
How do you keep a septic system healthy?
To care for your septic system, make sure to sign up for a service contract that includes an inspection at least every three years. Use water efficiently to avoid overwhelming the septic system. And be sure to use your toilet to dispose of nothing other than human waste and toilet paper, or you’re asking for trouble.
Are detergent pods bad for septic systems?
Detergent pods can pose a risk to children and animals, who might accidentally consume them. But if you’re a fan of the convenience, choose an eco-friendly detergent pod made without dyes, chlorine, phosphates, enzymes, or optical brighteners. Harsh chemicals can interfere with the natural bacteria that break down waste in your septic system, so don’t do anything to upset that.
How many daily loads of laundry are safe to do with a septic tank?
Good question! The amount of daily loads you can wash with a septic system varies depending on the size and capacity of your tank. To be safe, experts say it's best to limit the number of laundry loads to no more than four per day to avoid overload. More than that, and you might be dealing with a headache, such as clogs or backups!
A high-efficiency washing machine and septic safe detergents, such as the ones we've highlighted above, can also help prevent problems down the road with your septic system. Our top choice is ECOS Liquid Laundry Detergent with Built-In Fabric Softener. We love that it's compatible with all sorts of washing machines, plus it's gentle on sensitive skin and biodegradable.
Why Trust The Spruce?
Camryn Rabideau has been a freelancer writer and product tester for The Spruce since 2017, and covers a range of home products from bath sheets to high-efficiency washers. For this piece, she considered the ingredients, labels, effectiveness, value, and environmental impact of several top laundry detergents that are safe for septic systems.