This type of pottery is not waterproof and is more susceptible to breaking.
Firing ceramics in a kiln is the most practical way to make pottery food-safe and waterproof. Clay bisque-ware that has only been fired once is not yet waterproof or food-safe until the glaze is applied and subsequently fired again. Before gas and electric kilns, traditional ceramics were fired in ground kilns at low temperatures around 1000 degrees Fahrenheit, or simply dried in the sun to harden. This type of pottery is not waterproof and is more susceptible to breaking. If you do not have access to a gas or an electric kiln, you can try pit-firing your pottery. This process should be constantly supervised and is not ideal for beginners.