Septic Tank Operation

It's commonly misunderstood that septic tanks take years to refill, and need to be pumped out when they look "full". In a properly functioning septic system, the tank is always full and the liquid level inside the tank should always remain at the same level, about one foot down from the opening of the tank. Full but not overflowing. And once the tank is emptied out after pumping, it takes a week or less to refill back to it's previously "full" level. We can actually pinpoint the number of days it will take for the tank to refill based on the number of residents in the house. The average person generates 50 gallons of wastewater per day. If you have 4 people living in a house with a 1000 gallon tank, 50gal/day x 4 people = 200 gallons a day. So the tank will be refilled with water in 5 days.

We see it time and time again. Someone will will open the lid of a septic tank and be alarmed to see that the tank is nearly full, but not overflowing. Even if they aren't experiencing any issues in the house, they will call us in a panic requesting that the tank needs to be pumped ASAP because it's full. When in reality, this is normal. It's the operating level of the tank (PICTURED BELOW). It's always nearly full, because the drain pipe for the tank sits near the top of the tank. ​The purpose of a septic tank isn't to trap and retain all the waste water you generate. It's to separate the incoming liquids and solids. Trapping the solids in the tank, while allowing the liquid to pass through the tank to the leach field. The leach field is constantly taking water from the tank and absorbs it through the dirt, back into the ground. BUT! If you do have an overflowing septic tank, there are a few reasons that could be causing this and will need further diagnosing. If the tank can't drain, then the water has nowhere to go except out the top, or worst case, backing up into the house. Pumping out an overflowing septic tank is only a temporary fix that usually lasts less than a week in most cases. Long enough for the tank to refill from daily water usage. And unless the problem is diagnosed and corrected the tank will keep overflowing.

It's important to have the septic tank cleaned out periodically, every 3-5 years on average. All the solid waste is constantly being trapped inside, building up and accumulating in the tank. If sludge buildup on the in the tank becomes excessive, it begins to push out of the tank through the outlet baffle. 

The trapping and settling of solids in the tank is assisted with the help of a component called a baffle. A properly designed tank will have 2 baffles minimum. One at the inlet of the tank and one at the outlet of the tank. The baffle at the inlet is designed to direct incoming wastewater downward. Moving the heavier solids to the bottom of the tank and minimizing incoming water turbulence in the tank. It also prevents the floating scum layer from crowding the inlet pipe, potentially causing a blockage. Then there's the outlet baffle. This is the most important baffle in the tank. It allows the "clear water" from the middle liquid section of the tank to exit and prevents the floating scum layer in the tank from flowing out into the leach field, Causing a plugged leach field and premature system failure. And on newer systems the outlet baffle will be equipped with a filter to catch and prevent even more solid matter from exiting the tank. This filter will often times require cleaning every 6 month.