The Basics
What a Septic Riser Does
A riser is a short shaft fitted to an opening on top of the tank, brought up to the surface and capped with a lid. On many older tanks those openings sit under the lawn, so every visit starts with a shovel. With risers in place:
- Pumping and inspection visits start without digging.
- The effluent filter, which needs regular cleaning, is easy to reach.
- You can see the lids, so they don't vanish under a new patio or a snowbank.
Risers also make the county's three-year inspection easier; see POWTS inspections.
Local Rules
What Wisconsin Code Says About Risers and Lids
For tanks built to current code, Wisconsin's tank standard sets where the openings finish (SPS 384.25):
- Septic tank manholes reach to within 6 inches of finished grade.
- Openings over a pump or dosing equipment stand at least 4 inches above grade.
- Holding tank service openings stand at least 4 inches above grade.
- Covers at or above ground on openings wider than 8 inches need a locking device or another way to keep people out, plus a permanent warning label about entering the tank.
Owners also have to keep access covers locked or secured except during inspection or service (SPS 383.52).
Permits. For changes to an existing system, the state requires a sanitary permit when a holding, treatment or dispersal component is added or replaced (SPS 383.21). A riser isn't named on that list, but county ordinances can add their own rules, so check with your county's sanitary office.
How It Works
How Septic Riser Installation Works
- Find the tank and each opening: the inlet side, every compartment and any pump chamber.
- Dig down to the tank and expose each opening.
- Set and seal the riser so soil, roots and groundwater stay out.
- Fit a secured lid at or near grade.
- Backfill and regrade around each riser.
If the tank is due for septic tank pumping, doing both on one visit saves opening the ground twice. Holding tanks have their own access rules; see holding tank pumping. Our Green Bay septic pumping and Greenville septic tank pumping pages cover buried lids too.
Our Services
Septic Tank Locating
Lost track of your tank? It happens after buying a house, or when the last pump-out was years ago. We find it on every pump-out, and we also locate tanks as a job on its own, say before you build a deck or addition. Current code keeps a septic tank at least 5 feet from a building (SPS 383.43), so know where yours is before anything goes in the ground.
Where to look first
- Your county's permit file. The county's zoning or land services office can share what's on file, which may show where the tank sits.
- Old pumping receipts or inspection reports. Some include a sketch.
- The sewer pipe. Find where it leaves the basement wall. The tank is out from that side of the house.
FAQ
Septic Riser Installation FAQ
Can I put a riser on my tank myself?
Opening a septic tank is risky. Tanks can hold dangerous gases (EPA), and a lid that isn't secured can let a child or pet fall in. If you do any work yourself, check your county's rules first.
How many risers does my tank need?
Usually one for each opening the code calls for: over the inlet, over each compartment and over any pump (SPS 384.25). A two-compartment tank with a pump chamber can need three or more.
Will a riser make my system freeze?
An uncapped riser lets cold air into the system (U of M Extension). Keep every lid on and secured. Our guide on how to keep septic from freezing covers the rest.