Today, I got a call from a nice lady confused of why she needed a septic inspection when it was only a year old. I can totally understand the why. She paid over 15,000 dollars for this septic system, why does it need inspected all ready. She stated that it was a basic septic system, and doesn’t know what all the fuss was about. I told her it’s a real good idea to have your septic system inspected periodically to be sure it is functioning as designed.
She scheduled, and I came out. I came out to find a pretty complicated septic system. There is a computer running the whole show, and someone had opened it up and messed with the timers.
Septic System Control Panel
Here is a control panel for a septic pump. It is controlling the on/off time of the pump. Now at this location, this septic system was engineered to time-dose a sand filter only 20 gallons of effluent every 1 hr and 45 minutes. And it is to run this setting forever. Now you may ask, “how do you know how much water is being pumped, there’s no flow gauge or flow meter inline?” Now this is where things get a bit tricky.
First you must find the volume of the pump tank. LxWxH. That is your volume in cubic feet. In this tank we were 3 feet x 6 feet x 4 feet. That is 72 cubic feet. Now we need to convert cubic feet to gallons. There is 7.48 gallons per cubic foot. So we multiply the two. That gives us 538 gallons. Now, we need to figure out the gallons per inch. The tank is 4 feet deep, so we divide 538 by 48 inches. That gives us our gallons/inch. About 11 gallons of water per inch.
Now we can see how much the pump is pumping. I took a depth measurement of the water in the tank. Then turned the pump on for exactly one minute. I need to know what this pump is pumping per minute. I got 5 inches of drawdown in one minute. At 11 gallons per inch, we are pumping 55 gallons per minute. The pump is doing great and the sandfilter is accepting water at an acceptable level.
Now here’s where the problem is. I found the on-time for the septic pump at 1 minute 45 seconds on. That’s over 90 gallons per dose. This is over the maximum by nearly 4 times the acceptable level. This now explained to me, and the homeowner why the sandfilter was so soggy. It was getting slammed too hard all at once. Remember this septic system was designed to have 20 gallons per dose. This system was heading down the road to failure quickly. And it was only a year old.
Here’s a picture of the septic system with the lids opened.
Septic Tank Pumping
The lid closest to me is the solids handling tank. It was nearly empty. One inch of scum and zero sludge. Second compartment is the clarifying chamber. It was also empty with zero sludge and zero scum. But there is a filter in this one that needs cleaned. I will show a picture of that in a second.
The furtherest lid is the pump compartment. It’s designed to be a surge tank and gather enough effluent to push it out to the sandfilter. But only time dosing it 20 gallons every hour and 45 minutes.
The first two compartment of this septic tank are what normally needs pumped. About every 5 years if used properly. If one person lived on this system, it could easily be 15 years between septic pumpings. A family of 9 or more would be pumping this more frequently. Sometimes every 2-3 years. Remember, this system will only handle what it was designed to process. In this example, it is designed to handle 360 gallons of wastewater per day. And yes, showers, baths, laundry, and cleaning is included in this amount. With a system like this one, if you exceed the amount, an alarm will go off asking you to back off until it can catch up.
Part of the inspection I check to make sure all alarms are functioning. We want to make sure it will tell you that something is wrong. There is a silent switch on all alarms. Let me assure you that this doesn’t mean you fixed it. It means you acknowledge the alarm and are doing something to fix it.
Here is the septic filter I was talking about earlier. I am taking the picture after it was cleaned, so you aren’t seeing it all goopy and stuff sluffing off of it. It’s not too pleasant, but it’s job is vital on how long this system can function.
There was one homeowner that was tired of cleaning it yearly, so he threw it away. Well the filter is designed to trap particles from going into the sand filter and plugging it up. And yes he plugged up his sandfilter in 5 years, and needed to be replaced. Another $5,000 – $7,000 dollars for a new sand filter. Seems like I’d keep it in and keep it clean.
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