Cooking with RO Water: Best Lentil Soup

You pick the best produce at the store for cooking—so why would you overlook the main ingredient for your coffee, tea, and soup? No recipe calls for trace amounts of chlorine, yet a weak water filter can let all those impurities leach into you food and drinks! In the kitchen, water quality counts for a lot more than we realize. Main ingredients set the standard for the rest of the dish. So for water-based recipes, what comes out of your tap deserves special attention. Good water with an affordable home RO system filters gets your water-based drinks and soups tasting even better. Plus, clean water helps keep your family healthy! This season, we were inspired by an listing. By adapting some notes and ingredients—like utilizing our RO filter—we’ve created a yummy, water-based soup that’s perfect for fall.


  • 1 pound sausage
  • 2 carrots, peeled and diced
  • 1 medium onion, chopped
  • 2 stalks celery, chopped
  • 2 cloves garlic, minced
  • 3 teaspoon dried basil
  • 2 teaspoon dried oregano
  • 1 cup dry lentils (rinsed)
  • 1 (14.5 ounce) can crushed tomatoes
  • 8 cups RO water
  • 1 (10 ounce) bag frozen spinach
  • 2 tablespoons apple cider vinegar
  • salt and pepper to taste


1. Warm your large soup pot over medium-high heat and add in your sausage. Cook and break up sausage into crumbles, about 8-10 minutes. Remove sausage with slotted spoon and set aside on a plate lined with paper-towel.

2. Turn heat down to medium. Add onion, carrots, and celery to the grease. Cook until onion is tender. Stir in garlic, oregano, and basil and cook for another 2 minutes.

3. Add in RO water, tomatoes, and lentils. Bring pot to a boil, then reduce to simmer and return sausage to pot. Cover and let it simmer for at least an hour.

4. Before serving, add in spinach and stir until it wilts. Add vinegar, and season to taste with salt and pepper. (We liked a good tablespoon of pepper!)

If you aren’t using purified water for cooking, you’re missing out on some big, clean flavor. We like using water filtered by reverse osmosis (or RO for short) for recipes because it purifies the water in multiple stages. With RO filtration, fancy “prefilters” get rid of sediment and particulate matter.  The process clears out the taste and smell of chlorine in your water, too. Pressurized filtration in RO systems gets rid of any other dissolved solids, and carbon filters give the water a final polish before it gets to your faucet. Try cooking with specially-filtered RO water to give your favorite recipes a clean flavor-boost and let us know what you think of the taste. We hope you enjoy the recipe!