When anything more than water and soapy bubbles washes down your tub drain, it can lead to clogging, but the main culprit of clogged bathtub drains is hair. It could be pet fur or long human hair, but when it mixes with the other stuff in the water, it can stick like glue to the ...
or vents that are close to the drain line you are plunging. This step might not be needed to clear a toilet, but it certainly is if clearing a blocked sink or tub. Persist: don't give up too soon. We have successfully un-blocked recalcitrant clogged toilets that did not respond at ...