If you have just bought a home, you may not know whether it has a septic tank or is connected to a sewer system. Both systems dispose of wastewater from your home, but the septic system is an individual unit that belongs to you as the homeowner and is your sole responsibility. A sewer system is owned by your local government and connects all the homes in your area. Sewer systems are normally connected with community water systems.
Inspect your property carefully. Some septic tanks, especially if you live in a mobile home, are easy to spot because they are accompanied by a large, rectangular or cylindrical lump of earth that covers the drain field. If you can clearly see a single, unnatural-looking hill fairly close to your home, a septic tank is likely to be there.
Consider the location of your home. Sewer systems are not cheap, and the area has to have enough homes to support the system's maintenance. If you are in a subdivision or busy neighborhood, you're probably on a sewer system. If yours is the only home or one of a handful of homes in a rural area where each property consists of several acres, you are more likely to have a septic system.
Check your bills. Sewer systems are not free, so if your house is attached to a community sewer system, you can expect to be getting bills from it. Check your garbage or water bill for sewer fees if the sewer system is not billing independently. You will not receive a bill for your septic tank. If in doubt, call your local sewer and/or water management agency and ask whether your address is connected to a sewer system.
Get a copy of the records for your property from your municipal government. The blueprints, building permits and property records for your home will show whether the structure has a septic tank or has ever had a septic tank.