Does Washing Lentils Remove Pesticides Effectively?

December 7, 2025 •

3 min read

According to a 2020 report from the Environmental Working Group (EWG), glyphosate residues were found in a majority of conventional bean and lentil samples tested. This raises a critical question for home cooks: does washing lentils remove pesticides and is it enough to ensure your food is safe?

Quick Summary

Washing and rinsing lentils helps remove dirt, dust, and some surface-level pesticides. It is not effective for systemic pesticides absorbed into the plant. Choosing organic lentils offers the best protection from chemical residues.

Key Points

Systemic vs. Surface Pesticides: Washing removes external surface pesticides but cannot eliminate systemic ones absorbed into the plant, such as glyphosate.
Washing is still essential: Rinsing lentils removes dirt, debris, and excess starch, which improves the texture and cleanliness of your final dish.
Organic is the best option: To avoid systemic pesticide exposure, buying certified organic lentils is the most effective method, as they are grown without synthetic pesticides.
Washing techniques matter: For best results, sort lentils to remove pebbles, and rinse thoroughly under cool water with mechanical action (rubbing) until the water runs clear.
Soaking offers additional benefits: Soaking lentils can aid in digestion by breaking down complex sugars and phytates, and may further reduce some residues, but is not a substitute for buying organic.
Washing alone is not foolproof: The effectiveness of washing depends on the specific pesticide's chemical properties, with some being much harder to remove than others.

The Different Types of Pesticides on Lentils

Not all pesticides are created equal, and their chemical properties determine how they interact with food. For lentils, the two main types to consider are systemic and surface pesticides. Understanding this distinction is crucial for appreciating the limitations of washing.

Systemic vs. Surface Pesticides

Systemic pesticides are designed to be absorbed into the plant’s tissues, protecting it from the inside out. These are often sprayed during the growing season. Since the chemical is literally in the food, no amount of washing will remove it. Glyphosate, which is often used as a desiccant on conventional lentils right before harvest, is a prime example of a systemic-acting chemical that can be absorbed.

Surface, or non-systemic, pesticides remain on the exterior of the legume. These are applied to protect the plant’s surface from pests. Because they are on the outside, they are vulnerable to removal through mechanical action like rinsing or rubbing.

The Effectiveness of Washing

Washing lentils with plain water is surprisingly effective for removing surface contaminants. Studies have shown that rinsing with tap water can significantly reduce residues of loosely attached pesticides. However, the effectiveness varies greatly depending on the specific pesticide’s properties, such as its water solubility and how it bonds to the food's surface. For example, one study found washing could remove over 90% of some pesticides but less than 50% of others. The mechanical action of rubbing the lentils together during rinsing is likely a major factor in dislodging residues.

Step-by-Step Guide for Cleaning Lentils

While washing cannot eliminate all risks, it is a crucial step for removing dirt, debris, and some surface residues. Here is the recommended process:

Sort the lentils: Before washing, spread the dry lentils on a baking sheet or light-colored plate. Look for and remove any small pebbles, damaged legumes, or debris that may have mixed in during processing.
Rinse thoroughly: Place the sorted lentils in a fine-mesh strainer. Run under cool, clean water, tossing or rubbing the lentils with your hands. Continue until the water runs clear, which indicates that most of the dust and dirt has been washed away.
Consider soaking: Soaking lentils before cooking can offer additional benefits. It can help improve mineral absorption and reduce gas-causing compounds by breaking down complex starches and phytates. For most lentils, a soak of 30 minutes to 2 hours is sufficient, but remember to rinse them again afterward.

Conventional vs. Organic Lentils: A Comparison

For those concerned about pesticide residues, the choice between conventional and organic lentils is important. Here is a side-by-side comparison of the key differences:


Feature	Conventional Lentils	Organic Lentils
Pesticide Use	Sprayed with a variety of pesticides, including desiccant herbicides like glyphosate, right before harvest.	Grown without synthetic pesticides. May still have trace amounts from environmental drift, but levels are significantly lower.
Residue Levels	Can contain detectable levels of multiple pesticides, including systemic ones that cannot be washed off.	Generally free of pesticide residues. A 2011 report even found residues in organic-labeled lentils above MRLs, highlighting the need for vigilance.
Preparation Needs	Requires thorough washing to remove dust, debris, and surface residues. The effectiveness against systemic pesticides is limited.	Still requires washing to remove dirt, but carries a much lower risk of chemical residue exposure.
Cost & Availability	Generally more affordable and widely available in most grocery stores.	Typically more expensive and may have more limited availability, especially in certain regions.

Conclusion: Making an Informed Choice

Washing lentils is an essential practice for food safety, primarily to remove dirt, dust, and debris. For surface-level pesticide residues, thorough washing with water, combined with gentle rubbing, can offer a degree of reduction. However, it is fundamentally ineffective against systemic pesticides like glyphosate that are absorbed into the legume's core. For consumers seeking to minimize exposure to these internal chemical residues, purchasing certified organic lentils is the most reliable solution. The decision ultimately comes down to balancing cost, availability, and your personal comfort level with potential pesticide exposure. Whether you choose conventional or organic, a proper wash and sort is always recommended. For further details on pesticide levels in specific foods, the Environmental Working Group (EWG) website is a helpful resource for consumers, especially their 'Dirty Dozen' list.

Frequently Asked Questions

Studies suggest that rinsing produce with plain tap water is just as effective as using special produce washes, vinegar, or salt water for removing most surface pesticide residues. Some specialty solutions might help, but the mechanical action of rubbing under running water is key, and simple rinsing is effective enough for most situations.

Glyphosate is a widely used herbicide. It is often sprayed on conventional lentil crops as a desiccant, or drying agent, just before harvest. This allows the chemical to be absorbed into the plant, meaning it can't be washed off and becomes a residue concern.

Yes, absolutely. Washing conventional lentils is always a good practice. It removes surface-level dirt, dust, and debris that can affect taste and texture, along with any external pesticide residues that may be present.

Yes, all dried lentils should be washed before cooking, regardless of their color or type. This practice is necessary to remove any field dust, storage residues, and impurities that might have been picked up during packaging.

Cooking processes, especially boiling, can contribute to reducing pesticide residues through volatilization or thermal decomposition. However, like washing, cooking is not guaranteed to remove all types of chemical residues, especially those absorbed deeply into the food.

Beyond removing some surface pesticides, the main purposes of washing lentils are to remove visible impurities like dirt, dust, and potential pebbles, and to rinse away excess starch that can cause a gummy texture when cooked.

The only way to be reasonably certain of avoiding pesticide residues is to buy certified organic lentils. Organic farming standards prohibit the use of synthetic pesticides, significantly reducing the risk of contamination.