The typical dal water ratio is 1:3. This ratio will work if you serve dal with rice.   Sometimes I enjoy thicker dal with roti and naan, so I reduce the water ratio to 2.5 cups per 1 cup of dal. Also, soaking affects the total water required. The longer you soak the dal, the less water you would need. The typical 1:3 dal water ratio is proper to unsoaked dal.