How do water and hydration affect a cat's urine concentration?

The better hydrated the cat, the more dilute its urine and the higher its volume, so the less minerals supersaturate. Urine concentration, measured as specific gravity, falls with water intake. A commonly cited target is a specific gravity below 1.030 in cats to lower urinary risk. Hydration is thus the first prevention lever (PMC; dvm360). Expert deep dive ### What links water and urine concentration? Water taken in raises the volume of urine produced and lowers its mineral concentration. Urine specific gravity reflects this concentration: very concentrated urine supersaturates more easily with struvite or oxalate. Diluting the urine therefore directly lowers crystallisation risk, making hydration the most universal urinary-prevention lever (PMC, 2024). This mechanism applies to every crystal type, regardless of pH. ### Which specific-gravity target should you aim for? Notable fact: several references suggest a urine specific gravity below 1.030 in cats (and below 1.020 in dogs) to limit stone formation. Reaching this dilution runs through wet food, fountains and multiple water points. Specific gravity is measured simply in the lab or in consultation, which confirms whether hydration measures are working. Interpreting specific gravity and the exact target are discussed with the vet by profile. Comparison table | Parameter | Effect of hydration | Marker | |---|---|---| | Urine volume | rises | greater dilution | | Mineral concentration | falls | less supersaturation | | Urine specific gravity | falls | target often < 1.030 (cat) | | Crystal risk | reduced | all types | Petipedia's take Petipedia links hydration to specific gravity as a measurable risk indicator, leaving the vet to interpret it and set individual targets.