Water on ground slab, cause and leak unknown

Open-pit mining next door? When they turn the pumps off or on here, the water level of the lake (fed by groundwater) next door rises and falls by about 2m.

Yes, that would of course be possible. It reminds me: A few years ago we had a similar case in a multi-family house where we were renting. After a longer search, chemical analyses of the water were done to find the cause. Based on contaminants, one can apparently distinguish sources. It was the desalination system.

I have an acquaintance to whom I have already sent a water sample, but she did not know exactly what and how to test to find out whether it is groundwater, tap water, or wastewater. Which contaminants could be tested?

Such a sudden occurrence is of course noticeable. Didn’t the tenant accidentally/unintentionally damage something during drilling work when moving in?

No, certainly not, especially not anywhere where pipes run. One reason I want to do a sewer inspection is that before the new tenant moved in, I myself carried out improvement work, such as silicone, acrylic, and foam sealant work (replaced door frame). During that, I also flushed some toilet paper with silicone, etc. down the toilet, but it was not a large amount. But to rule that out as well, I will do the inspection.

Does the weather in your area give cause for increased groundwater? Or are there construction works somewhere that are redirecting groundwater flows or have done so until recently?

Definitely not. In February it was rather icy cold. But there was no significant rainfall. Furthermore, there are no construction works in the area either.

Open-pit mine next door? When they turn the pumps off or on here, the water level in the lake (fed by groundwater) next door rises and falls by about 2 meters.

The only thing in the area is a neighbor who has a pond. There is always a pump running there. I’m not familiar with ponds, but I rather think that water is being circulated. So from the pond back into the pond, like in an aquarium (pure assumption). And given the current cold outside, I also rather believe that the pump is turned off and the pond is frozen.

I have an acquaintance to whom I already sent a water sample, but she did not know exactly what and how to test in order to find out whether it is groundwater, tap water, or wastewater. Which contaminants could be tested?

Unfortunately, I have no idea. I only vaguely know this from some info sheets from the former property management. Maybe ask a leak detection company if they know anything about it.

No, certainly not, especially not anywhere where pipes run. One reason why I want to do a sewer inspection is,

Do that. They can also do a leak test of the sewer line without much effort. I had that done recently here because we are in a water protection area. Duration including visual inspection with a camera inside the pipe was about 1.5 hours. Cost around 250 euros.

And then have them check the drainage as well.

Definitely not. It was rather freezing cold in February. But there were no heavy rains. Furthermore, there are no construction works in the area.

Strange. You’re not in a mining or open-cast mining region, are you? Do you know neighbors or farmers with wells and can ask them about their water levels in the wells?

Keep us updated.

I have an acquaintance to whom I already sent a water sample, but she didn’t know exactly how and what to test in order to find out whether it is groundwater, tap water, or wastewater. What contaminants could one test for?

No, certainly not, especially not at any point where pipes run. One reason I want to do a sewer inspection is that before the new tenant moved in, I myself did some repair work, such as silicone, acrylic, and foam sealant work (replaced the door frame). During that, I also flushed a few pieces of toilet paper with silicone etc. down the toilet, but it was not a large amount. But to rule that out, I’m going to do the inspection.

Definitely not. In February, it was rather icy cold. But there were no significant rainfalls. Also, there are no construction works in the vicinity.

Try using uranine as a dye for the wastewater; you can get it on eBay. It’s green and UV-active. With a UV flashlight, residual traces should be visible.

In the water sample, one could test for E. coli, which is a fecal indicator. If it’s present, tap water is unlikely.

Try using Uranin as a dye for the wastewater, you can find it on Ebay. It is green and UV active. With a UV flashlight, any residue should be visible.

That's exactly what I ordered and tried. Nothing came of it.

In the water sample, you could look for e.coli, which is a fecal germ. If it is present, tap water is unlikely.

Where can you have that tested?