I was in the livingroom and getting a headache. Someone asked me to turn on my EMF meter, and it was red hot 100+ mG magnetic radiation. I turned off things in living areas, but nothing upstairs made a difference. Could not find anything in the living areas.
Went downstairs and the basement lights and stair stepper was on, causing 300 mG in basement also. Once those were unplugged, dropped to norm levels. We had encountered "net current". Wife's Insomnia went away, but my son's anxiety spike took several weeks to recover. Using my gaussmeter, voltage probe, and other tools determined that 30% of my outlets and basement light sockets are cross-connected to other circuits in other areas - creating huge magnetic radiation when energized.
Unplugged those, used extension cords and plug in lamps, as needed as a temporary fix. No more worry about turning on something, causing hotspots elsewhere.
I think every family should have EMF meters. It is better to know and take action then after the fact.
If you or family live near a high powerline, it would depend on how much power is in the high power line. 700kV, 400kV or 66kV? Best way to check with Gauss meter and EF meter.
http://www.emfwise.com/distance.php - On the bottom #5 are standards to get to below 2mG. I recommend the standard is too lenient, it should be the distance to get to < 1mG.
https://emfinfo.org/guidelines-distance.html - 700 ft for 400kV, 1000 ft for .5 Volts on skin https://emwatch.com/power-line-emf/ - mentions 400kV, min of 200m to get down to .5 mG https://www.safespaceprotection.com/emf-health-risks/emf-health-effects/power-lines/ - Heres a pic on 765kV, even at 2000m, there is stunted growth.
Another thing to consider is to get a home remediation kit from EMFSol.com https://en.geovital.com/how-close-is-too-close-when-living-near-transmission-power-lines/
There is a company that does Active Magnetic Shielding (Field Cancellation) $15k - $40k for homes to actively cancel out magnetic fields from high voltage powerlines. Shielding efficiencies of 65% to 95% are typical.
Wiring Errors photos / diagrams
Video by master electrician Karl Riley on Tracing EMF in buildings
Videos on EMF