Measure the drinking instead of estimating it
Time at the bowl is a clue, but volume is evidence. Fill her main water bowl to a marked line or pour in a measured amount each morning, then measure what remains a day later, remembering that evaporation and a second pet sharing the bowl will blur the figure — if another cat drinks from it too, say so in your notes and observe her visits as well. Count roughly how many separate drinking visits she makes across a day and whether she now seeks water in new places: a dripping tap, a glass left on a table, a second bowl she previously ignored. Note whether she laps briefly and often or settles for long drinks, and whether she hovers near the bowl without drinking, which is worth mentioning in its own right.
Pair the water record with what leaves her body
Drinking only tells half the story, so track the litter box in the same week. In a clumping litter, note whether the wet clumps are larger, more numerous, or both, and how often you are scooping compared with your previous routine. Record any accidents outside the box, any night-time trips you hear, and changes in stool alongside the urination notes. A cat drinking much more and producing much more urine presents a different picture from one who visits the bowl often but passes little. If you use non-clumping litter, note how wet the tray is at each full change and how often changes are now needed. Keep the routine itself unchanged while you measure, so the comparison stays honest.
Log weight, appetite, and energy in the same window
Increased thirst in a senior cat often travels with other shifts, and the combination is what your vet will weigh. Weigh her if she tolerates a scale, or run your hands along her ribs, spine, and hips weekly and note whether the bones feel more prominent under the same coat. Record her appetite meal by meal in simple terms — finished, half, refused — and whether she seems hungrier despite losing condition, or less interested in food altogether. Note energy and behaviour: sleeping more, seeking warm spots, vomiting, a rougher coat, or bad breath you have not noticed before. Date every entry, because the speed of change matters as much as the direction.
Rule out the ordinary explanations at home first
Before the appointment, check the simple causes so you can report them as ruled in or out. A switch to mostly dry food, a warmer house, a new bowl position near a radiator, or a recently changed routine can all raise drinking modestly. Note whether the increase began around any food change, any new cat in the home competing at the bowl, or any period of hot weather. Refresh her water frequently while you track; stale water can make a cat drink in long sessions when it is finally clean, distorting your record. Do not restrict her water to test her — a thirsty senior cat should always have free access, and limiting it could harm her and corrupt the very measurements your vet needs.
Treat increased thirst as a reason to book, not to wait and watch
Of all the changes on a senior checklist, a clear rise in drinking is one to raise promptly rather than saving for a distant routine check, especially if it pairs with weight loss, bigger litter clumps, appetite change, or vomiting. Call the clinic, describe your measured amounts and the accompanying signs, and let them set the timing. At the visit, present the water measurements, litter notes, and weight trend together, and ask what they will test, what home monitoring they want next, and what level of thirst or weight change should trigger a faster return. If she stops eating, becomes lethargic, vomits repeatedly, or seems unable to settle, seek advice the same day.
With measured water amounts, litter observations, and weight notes filed in her KinsLe Pet Passport, the conversation at the vet check starts from solid numbers instead of a worried recollection.