The dimensions of a 500-gallon concrete septic tank can vary from manufacturer to manufacturer, but the tank is large enough to handle the wastewater of a small home with up to one bedroom. Keep in mind that some states have a minimum septic tank size, and this often starts at 750 gallons. A 500-gallon septic tank may be too small to meet local regulations.

Baking soda does very little to nothing for a septic tank, but it can help unclog a drain or clean out a garbage disposal. Rotten tomatoes and yeast are the best ways to increase the bacteria in your septic tank naturally. You can add these to your system once every three months.

Your septic tank naturally contains the beneficial bacteria it needs to function, so you typically don't need to add more. However, if you wish to replenish the bacteria, you can use natural methods. For example, you can add three overripe tomatoes to your garbage disposal or flush 1/4 ounce of active yeast down the toilet every three months. While store-bought septic enzymes and chemicals are available, many experts consider them unnecessary and potentially harmful. The most effective way to maintain a healthy bacteria population is to avoid using chemical drain cleaners, which can kill the good bacteria in your system.

A septic tank lid is often 1 foot underground, but it could be just 4 inches from the surface or 4 feet deep. For septic tank lids that are closer to the surface, you’ll have an easier time locating them just by looking for signs in the yard or using a metal probe. But for septic tanks that are buried deeper underground, you’ll need to hire a pro with specialized equipment to track down the lid without risk of damaging utility lines.