As you may have figured out by brousing
this site, pumping out your septic tank is a very important
part of keeping your system opperating. Adding an access port to your septic tank can give you an
advantage when pumping. The cost of digging up the lid and removing it, plus if you have access you
may find it does not need pumping. Below you can see a diagram of three tanks. The first is a septic t
ank with no access. The second is a simple access. And the third is the top of the line access.
This is a basic set up, the lids on either end must be located, dug up, and pryed off. This is the cheapest meathod for installation but will cost more to have pumped out due to increased labor.
This is a better setup, a six inch pipe has been permanently attached to the tank and a screw on cleanout cap is placed on the end. this setup allows for a visual inspection and pumping without digging.
This is the best setup, a commercial access lid is placed on top of a riser that allows access for inspection and quality pumping and the ability to have human access to the tank if necessary.
Access lids are a good add on for a septic system but it will opperate without it. so most installers that are competing on bids don't even mention it. Don't be afraid to ask them these accesses can be picked up at the same place where the tank comes from and will save a lot of trouble and money later.
Searching google from this site should bring you a response more targeted to the septic system.