What Is a Septic Tank Riser?

A riser is a pipe or shaft fitted over a septic tank's access opening that brings it up to or near the ground surface. A lid on top closes it, so the tank can be opened for pumping and inspection without digging.

Explanation

Florida's tank standards define a riser as "a pipe or conduit surrounding an access manhole and facilitating access to the inside of an onsite sewage tank" (Rule 62-6.013(2)(k), F.A.C.). For tanks made for use in Florida, the same rule says:

• The access openings over the tank inlet and outlet must reach to within 8 inches of finished grade. On tanks with more than one compartment or tanks in series, that applies over the first inlet and the last outlet.
• Risers must be watertight, and where a riser lid opens straight into the tank, the joints must be sealed to keep groundwater out.
• Each opening must be closed by a riser lid or manhole cover made vandal, tamper and child resistant, for example with a padlock, a twist-lock cover that needs special tools, a cover weighing 58 pounds or more, or a corrosion-resistant hinge and hasp.

Some tanks have their lids buried under the lawn. The EPA notes that when you look for a tank you "might find an access riser (black or green disc)". If your lids are buried, the company may charge about $50–$200 to find and dig them up at each visit. Adding risers costs about $100–$400. One guide quotes up to $1,000.

Florida's rule does not count replacing a broken tank lid as a repair (Rule 62-6.002(51)). Ask your septic company or permit office whether adding a riser to your tank needs any paperwork.

When to seek help

• A riser lid is cracked, loose, sunken or missing. Call a septic company.
• The lid has no lock, screws or other way to stop a child from opening it.
• Standing water or damp spots near or over the tank, which the EPA lists among septic warning signs.
• You pay for digging at every pump-out.

Learn more in what happens during a septic pump-out, septic tank safety and the septic pumping cost guide. Compare septic pumping companies.

Related terms

• Baffle
• Effluent filter
• Sludge and scum layers
• Septage