On Saturday we noticed a depression in the grass between the house and the paver walkway. This stake is a 36 inch survey marker at the top of the hole.
This is the same stake down into the hole until it hits dirt.
Oh, looking into the hole there is a sprinkler line so that might be the reason for the depression if the line is leaking. So I turned on the sprinklers to check for a leak. No leak was seen.
Well, back in 2005 we had the septic system abandoned and hooked up to city sewer. The proposal and receipt shows they were supposed to fill in the septic tank with dirt. Notice the seam between the 2 halves of the septic tank cover? Looks like the tank did not get filled and the heavy rain last night washed some of the dirt into the tank. A technician from the plumbing company is supposed to be here in the morning to evaluate the situation. Why did it take 16 years to develop? Very interesting!