Slow Cooker Lentils & Rice

I made 1/4 of this recipe and used a 1 1/2 quart slow cooker. It was very tasty!

2 c. dried lentils
2 c. uncooked long grain rice (white or brown)
1 c. chopped carrots
½ c. chopped celery
½ onion, chopped
8 c. water
1 c. vegetable broth
1 tsp. garlic powder
½ tsp. black pepper
1 T. salt
1 c. sliced fresh mushrooms, opt.

Place lentils, rice, carrots, celery, onion, water, broth, garlic powder, black pepper and salt in a slow cooker. Cover & cook on low setting for 7-8 hours. Stir in mushrooms 1 hour before serving.