Frequently Asked Questions

Mounds and Septic Systems

(Any specifics are based on Wisconsin code and regulations.)

What is wastewater?

Wastewater is all of the water that is used in a building and has to exit the building after it is used, i.e. toilets, sinks, floor drains, dishwashers, clothes washers, showers etc. ALL water used inside a building that has to go somewhere and be treated.

How is wastewater treated?

In a municipality that has a municipal wastewater treatment plant, all wastewater is directed to the wastewater treatment plant (through a sanitary sewer system) where the water is treated.

What if there is not a municipal wastewater treatment plant in the area where I live?

If you do not have access to a municipal wastewater treatment plant, then your lot will treat its own wastewater onsite using a type of POWTS (Private Onsite Wastewater Treatment System)

What is a POWTS?

POWTS (Private Onsite Wastewater Treatment System) is an acronym that means any type of onsite wastewater treatment system such as: mound system, in-ground system, holding tank, highly pretreated systems that all treat wastewater onsite.

What is effluent?

Effluent is wastewater that has been partially treated by going through a septic tank. Wastewater coming out of a septic tank is effluent.

How do I know if I will need a mound or a conventional (in-ground) septic system?

A soil test is required to determine what type of system is needed and all the design criteria of each system. Once a soil test has been completed on your lot, you will know what type, size, and location of system you will need. Herr Construction does perform soil testing year round.

What is the difference between a mound system and an in-ground system?

A mound system is a POWTS that is built above the ground by importing coarse washed sand. Mounds are designed to make certain the wastewater is treated through three feet of approved soil prior to coming in contact with a shallow soil limitations (see limiting factor). In-ground systems are installed where the soil limitations (see limiting factor) are much deeper. In-ground systems can treat the water through three feet of soil in the ground and still have room before the soil limitations.  

How do I know what my soil limitations are?

A certified soil tester performs a site and soil evaluation to determine the depth to the soil limitations (among many other things).

What is a limiting factor?

Limiting factors include high groundwater, bedrock, restrictive slowly permeable soil such as a massive clay, and seasonal fluctuating groundwater. Most systems must treat wastewater through a minimum of three feet of suitable soil prior to coming in contact with the limiting factor.

Do both types of systems have to be pumped?

Yes, both mound systems and in-ground systems must have the solids pumped out of the septic tank portion of the system on a regular basis. The state requires that all systems be pumped every three years if the tank has accumulated solids to a depth of one-third the tank depth.

How often should we pump our system?

The state requires all systems be pumped or inspected at least every three years. Older systems, or smaller systems with increased use should consider more frequent pumping. Some older systems typically get pumped annually as a method of trying to keep the system functioning.

Why is pumping beneficial for a mound or septic system?

An analogy would be that pumping a septic is like changing the oil in a car-it removes particulate matter that could cause major problems with the system eventually. As solids accumulate in the septic tank, the accumulated solids reduce the volume in the septic tank. By reducing the volume, the water moving through the tank has less retention time, and thus, moves more waterborne solids out of the tank to the distribution cell, causing clogging and eventual failure. By pumping and removing the solids from the tank, the system is cleaner.

Will additives help my system?

Short answer: No

Our saying is: If you just flush the money directly down the drain instead of buying additives, you’ll get the exact same results. (Not that we want you flushing money into your system).

How long will a septic or mound last before it eventually fails?

Mounds and septic systems designed and installed prior to the year 2000 AVERAGE 20 to 25 years of useful life prior to failing and needing to be replaced. Many systems fail sooner than 20 years, and many last well beyond 25 years, the AVERAGE is 20 to 25 years.

What causes failure of a mound or septic system.

Most mounds and septic systems fail due to accumulation of waterborne solids that seal off the pores of the soil. Once the soil is completely sealed off and doesn’t take water, the wastewater follows the path of least resistance, which could be up to the ground surface (failure) or back into the house or building (also failure).

What are ways to maximize the life of a septic or mound system?

1. Do NOT flush WIPES. Toilet paper should be the only paper product flushed into a system of any type. WIPES will cause major issues and cause the need for costly repairs.
2. Water softener and iron filter RECHARGE water should be routed so that it does NOT flow into the septic system. This is a code compliant way to really make a big difference on the lifespan of your system. Typically, water softener recharge empties into a sink or floor drain, both of which go to the septic system or mound.  
3. Minimize or eliminate use of a garbage disposal. Garbage disposal use WILL reduce the life of the system.
4. Do NOT pour cooking oils or grease down the drain.
5. Have your system pumped on a regular basis.
6. Make certain surface (storm) water is not directed TO your septic tank manhole covers. For best results your manhole covers should be six inches above the surrounding grade.

Can my manhole covers be buried?

               Wisconsin code allows you to have buried covers as long as they are within 6 inches of the surface. Covers that have a filter or pump beneath them cannot be buried.

Why do some manhole covers have chains and locks and others do not?

Per Wisconsin code, if a manhole is going to be exposed (i.e. not buried) it MUST be locked.

My system has an alarm. When the alarm activates what does that mean?

Most systems with an alarm have a pump tank. In systems with a pump tank, the alarm means the level is high which is an indication the pump did not pump down when it should have. It could mean the breaker to the pump has tripped, the pump is bad, the float switch is bad, or the electrical junction box on the side of the riser has an issue.  Please note that some systems have effluent filter alarms.

What can I plant on my mound system?

Mounds are seeded at time of installation to prevent erosion. Please note that the pipe inside the mound is only (approx.) one foot deep from the top of the mound. So, if planting on the mound do NOT use a tree spade, and plant only those items that start as seeds or can easily be planted by hand.

What are my next steps if my system fails?

If you have a mound, many mounds can just be rebuilt within the same (or enlarged) footprint where it is now. If you have an inground system, check at the county there MIGHT be a soil test on file that would show where a replacement system can be installed. If the county does not have a soil test on file, prior to replacing a system you will need a soil test to determine what you need. Herr Construction does perform soil tests year-round.

How often should I clean my effluent filter?

There are many types of effluent filters, some good, some not near as good. Depending on the type of effluent filter you have, it is recommended that you check the level in the tank twice per year. If normal both times, at least clean the filter once per year. If you have an elevated level in the tank, definitely clean the filter.

How do I know if my septic tank is at a normal level?

If you have an effluent filter (systems installed or replaced since the year 2000), the horizontal pipe that leads out of the tank from the filter is your best way to determine level in tank. The horizontal pipe leading from the filter out of the tank should always be approximately 90% above the water level. NORMAL level in a septic tank is at the very bottom of the pipe leading out from the filter. Should that horizontal pipe be under water, the level is elevated, and the filter should be cleaned ASAP.

What are causes of a high level in a septic tank?

If a septic tank has a high level, one of the causes could be that an effluent filter needs to be cleaned.

What could cause a high level in a septic tank if I do not have an effluent filter?

A high level in a septic tank that does not have an effluent filter could be caused by: a blockage in the outlet pipe, an outlet pipe that has collapsed, broken, or has severe solids build up, root intrusion in the outlet pipe, or a system that is at an advanced stage of a saturated condition and failure could be imminent.    

What are other signs I am having a problem with my system?

Other indications of a problem with the system include sewage backing up out of floor drain in lowest level of building, drains running slow, toilets flushing in a strange manner, sewage coming out of septic tank manhole, accumulation of sewage on the ground surface.      

What is the difference between a septic tank and a holding tank?       

A septic tank is the first treatment step for most in-ground septic systems and mound systems. A portion of the waterborne solids settle out in the septic tank prior to the water exiting the tank to a secondary or soil; treatment component. A septic tank is pumped of solids on a three year (or a more frequent cycle). A holding tank is used when the soil or site did not pass for any type of system. A holding tank receives all of the wastewater from the house (or building) and is pumped every time the tank is full. The average pumping frequency of a holding tank is once per month.     

I am getting a sewer gas odor in my house. Does that mean I am having a problem with my septic?

A sewer gas odor might mean there could be a septic issue, but in most cases sewer gas odors are not indicative of a septic problem. In most cases sewer gas issues inside of a house are caused by a sanitary sump crock being improperly sealed. Sanitary sump crocks if filled with smoke should not allow any smoke out. Check the top of the crock -is it bolted with a gasket? Is it caulked? Do wires and pipes that come through the top of the crock have a rubber grommet and caulk?  If you can see into the sanitary crock (no matter how small the opening) that’s where the sewer gases are coming from.

Where else could sewer gas smells come from?

More sources of sewer gas smell could be, drain traps that have evaporated from not being used. Think, a floor drain that never gets water, a sink, tub, or shower drain in an ‘extra’ bathroom that never gets used. Run water in those drains and the sewer gas odor should go away. Another source could be pipes stubbed up out of the lowest level floor as ‘future plumbing’. Other sources of sewer gas smell are a compromise in the vent system (a broken, cracked, or loose pipe), and a toilet wax ring that needs replacement.