In Texas we are required by law to have a contract with someone. We pay around $150 for a year and they are required to come out 3X a year to check it. The company we have been with have been really good. They are faithful on coming out to check it when they are scheduled to and gives us a report each time. We also have to get it pumped every two years at our own cost which is around $360. We are supposed to keep these "chlorine type" tablets (not the same as you would put in a pool). When you get it pumped, be sure that they pump all tanks. We have a total of 3 tanks underground. Only one had what you call a riser that comes out of the ground so it looks as if we only have just one tank. A lot of companies who are less than honest will just pump that one and not say or do anything about the others that might be there. That's what happened here I believe. We've been in our house since 2006 but the house has been here since 2002. Due to some water, air and electrical lines going over the two additional tanks, it was obvious that those two have never been pumped. If you don't pump the tanks in the timely manner you run the risk of burning up the pump which will result in expensive repairs. Get with your aeration company to see what they suggest on what you should do to keep it clean. Remember, that if you have multiple water functions going on at the same time, like shower, dishwasher, washing machine that it will cause your pump to work harder. So try to space them out if you can. If you have a large number of people living in your house, it is recommended to have your tanks pumped more frequently. Also, do not pour bleach, grease or any harsh chemicals into your drains. Also you aren't supposed to have a garbage disposal. And it's not a good idea to flush sanitary napkins either. I've been learning all about it as I've been here since this is my first time having one.