Grease the inside of a 6 to 7-quart slow cooker.

Cook the ground sausage and drain. Mix in the Italian seasoning with the sausage.

Break 3 of the lasagna noodles in half and arrange them on the bottom of the slow cooker. Top with half of the cooked sausage. Arrange 12 pepperoni slices over the top of the sausage. Layer with a third of the spaghetti sauce, half of the water, half of the ricotta cheese, and a third of the mozzarella cheese.

Break 3 more lasagna noodles and arrange them over the mixture. Add the remaining sausage and pepperoni and a third of the spaghetti sauce. Sprinkle the remaining water and ricotta over the top of the sauce, and a third of the mozzarella cheese.

Break the remaining 3 lasagna noodles and arrange over the top of the mixture. Add the rest of the sauce and mozzarella cheese. If desired, sprinkle with more Italian seasoning.

Cover and cook on low for 4 hours. Do not overcook or the noodles will get hard.

Serve with garlic bread and salad.