Once the probable source of the moisture has been identified, things can be done to attempt to remedy the issue.
First if a leaky tent seam is suspected and the leak only happens during a rain storm; see if there is actually a drip forming and remember the seam where it is occurring; treat the seams with a commercial seam sealer.
If water is happening without rain then seam sealing is unlikely to do much, IMO.
If water is seeping through the floor; typified by wet foot prints where you walk, but usually not puddles, then a waterproof ground cloth will usually solve the issue. I use a heavy silver tarp having found "footprint" style ground sheet very expensive for what you get (its can be much cheaper to get a cheap tarp and trim it to size if you want a foot print style groundcloth.
Canvas tents and occasionally other fabrics can leak if they are touched on the inside when wet. Touching can break the surface tension of the wet fabric and lets the water run through the touched spot. Completely drying the tent is usually enough to re establish the water resistance of the fabric (until it is again touched when wet).
Fortunately, I have not yet had a problem with leaky tent fabric or seams. However, I have heard that there are spray on products intended to make fabrics more water resistant... Scotchguard water shield comes to mind as a possibility, however there are others.
My dome tent in addition to having a porous floor, has a rain fly that does not adequately cover the tent sides in a heavy/driving this can result in leaks along the bottom 2 feet or so of the sidewalls, if the rain is heavy enough or driven by strong winds. During one wet year I made a rain skirt that covered the bottom 18 inches or 2 feet of the tent sides from transparent plastic, this worked about as well as covering the entire tent with a waterproof tarp, yet still allowed some ventilation and light to enter. Mostly I find the manufacturer's standard raifly is adequate for light showers.
I no longer try to use a tent heater; having gotten tired of the condensation and having found that a good sleeping bag is eough to keep me warm & toasty. If it is really chilly, I may fire up a small heater for a couple of minutes to reduce the cold shock of undressing before entering the bag. Once in the bag I turn the heater off. I try to maintain at least 16 square inches of both upper (near the tent peak) and lower (near the tent floor) ventilation, in an attempt to keep the interior atmosphere healthy. Note; if you try to use a heater, overnight, it may require much ore ventilation than this.
House training the puppy and making sure that he could get out if he needed, cured the pet leak.
Keeping the cooler and water jugs out side eliminated any possibility of puddles from them,
Hope it helps...
Enjoy!
