Best Laundry Detergents for Greywater Systems

Greywater systems can cut water waste and support sustainable landscaping — but only if the products you use are safe. The most important factor? Choosing the right laundry detergent.

What Makes a Detergent Greywater-Safe?

Not all eco-friendly products are created equal. When choosing detergent for greywater use, look for:

• Biocompatible (not just biodegradable)
• Low sodium content
• Free from synthetic dyes, fragrances, or softeners
• No chlorine bleach or optical brighteners

Biocompatible detergents go a step beyond biodegradable—they won’t harm soil structure or plant health even with long-term use.

Ingredients to Avoid

When scanning the label, avoid:

• Salt-heavy compounds (any ingredient starting with “sodium”)
• Borates, phosphates, and alkylbenzene
• Brighteners, colorants, synthetic scents
• “Whiteners” or chlorine bleach
• Pods or detergent with plastic coatings

Even some plant-based brands sneak in harsh chemicals. Shorter, simpler ingredient lists are often better.

Greywater-Friendly Detergents to Consider

Here are some of the most reliable options you can find in stores or online:

Oasis Laundry Detergent

• Truly biocompatible
• No sodium compounds
• Formulated specifically for greywater irrigation

ECOS Liquid Laundry Detergent

• Biodegradable and plant-based
• One sodium compound only
• Lightly scented with essential oils

Earth Breeze Laundry Sheets

• Compact and plastic-free
• Low-salt formula ideal for greywater reuse
• Easy to store, no mess

Trader Joe’s Liquid Laundry Detergent

• Low in salts
• No synthetics or dyes
• Natural essential oil scent

7th Generation Free & Clear

• USDA certified biobased
• Low salt levels
• Fragrance-free

Ever Spring (Target brand)

• Clear formula, no dyes
• Moderate salt content
• Budget-friendly greywater option

Detergents to Skip

Avoid brands like Tide, Downy, and Gain. These products typically contain:

• High concentrations of salt
• Artificial ingredients
• Harsh cleaning agents that harm soil

Tips for Using Laundry Detergent with Greywater

• Flush your system with fresh water occasionally to manage salt buildup
• Avoid powdered detergents—liquids or sheets are better
• Skip fabric softeners entirely (or switch to dryer sheets)
• Use cold water cycles to reduce residue

Final Word

Choosing a detergent for greywater irrigation isn’t just about eco-marketing claims. Look past the branding. Read the label. Prioritize biocompatibility and low salt content. With the right laundry soap, your greywater system will stay efficient, safe, and sustainable.