The 7 Best Detergents for Septic Systems in 2021

Keep your laundry clean without disturbing your septic tank

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Our Top Picks
"This biodegradable detergent has a concentrated formula that will leave clothes looking as good as new."
"This detergent is specially formulated to break down body odor, sweat, and other scents."
"This eco-friendly laundry detergent has a concentrated formula that's made mostly from plant-based ingredients."
"This high-efficiency detergent doesn't have any fragrance, so it's perfect for those with sensitive skin."
"This formula allows you to use less product per cycle, ensuring each bottle lasts longer."
"This powder detergent doesn't create suds, but it still removes dirt, grease, and stains from clothing."
"These laundry pods have a convenient 4-in-1 plant-based formula that removes stains, brightens, and more."

If you’ve previously lived in homes hooked up to the sewer, you might be surprised to learn there are a lot of restrictions on what you can put down the drain when you have a septic system. 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 be choosey about the cleaning products you use, and that includes laundry detergents. In general, you’ll want to look for a label on the bottle that says the product is “Septic Safe,” and it’s also beneficial to choose a biodegradable detergent with low levels of surfactants. Further, if you have an aerated septic system, you’ll probably want a high-efficiency or powdered laundry detergent to avoid excessive foam.

Here, the best laundry detergents for septic systems.

Best Overall: ECOS Liquid Laundry Detergent with Built-In Fabric Softener

Ecos Laundry Detergent

For an effective, yet eco-friendly detergent that will leave your clothes fresh and clean, it doesn’t get better than the ECOS 2X Liquid Laundry Detergent. 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.

This laundry detergent is free from dyes, optical brighteners, parabens, phosphates, and phthalates, and the formula is hypoallergenic and pH-balanced for those with sensitive skin. It includes a built-in fabric softener to save you money, and it works in all water temperatures and in both high-efficiency (HE) and standard washing machines.

The ECOS Laundry Detergent is biodegradable and safe to use in both septic and greywater systems, and people love the light smell and effective cleaning power of the eco-friendly formula.

Best Budget: 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 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. The 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.

Best Green: Seventh Generation Free & Clear Natural Liquid Laundry Detergent

Free & Clear 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, and as its name suggests, the detergent is hypoallergenic and fragrance-free, ensuring it doesn’t irritate sensitive skin.

The 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, users say a little bit of the plant-based formula goes a long way toward getting clothing clean.

Best Unscented: Method Free + Clear Laundry Detergent

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.

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 those beneficial bacteria. 

Best Concentrated: Solimo Concentrated Liquid Laundry Detergent

Many laundry detergents are diluted with water, which means you have to use more product per cycle. However, the Solimo Concentrated Liquid Laundry Detergent is a septic-safe formula that hasn’t been watered down, and you’ll be able to do up to 128 loads of laundry using the affordable 96-ounce bottle.

This detergent is available in several scents, including lavender, clean linen, and the unscented Free Clear. It’s compatible with both high-efficiency and standard washing machines, and the formula contains powerful stain fighters to leave your 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.

Best Powder: 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 popular 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 non-toxic, 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.

Best Pods: Dropps Stain and Odor Laundry Detergent Pods

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 its ingredients and packaging are sourced from suppliers that meet high-quality standards.

Final Verdict

If you're looking for the best overall detergent for septic systems, ECOS Liquid Laundry Detergent with Built-In Fabric Softener (available on Amazon) is compatible with all sorts of machines, is gentle on sensitive skin, and is biodegradable. Arm & Hammer Plus OxiClean Odor Blasters Laundry Detergent (available at Amazon) is a great option at a slightly lower price point, but still has powerful stain fighting properties and a pleasant scent.

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Article Sources
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  1. Ignatius Ip And E. Craig Jowett. The Effect Of Household Chemicals On Septic Tank Performance Receiving Dilute Wastewater. On-Site Wastewater Treatment X, 21-24 March 2004, doi:10.13031/2013.15795