You pollute each body of water inside an area you choose within range that is a cube up to 100 feet on a side. The water becomes murky and diseased for the duration.

While the spell lasts, the water is heavily obscured, and each creature that ends its turn within the water must succeed on a Constitution saving throw or else take 1d6 poison damage and become poisoned for 1 minute. A creature repeats the saving throw at the end of each of its turns, but only if it is no longer in the water. On a success, it ends the effect on itself.

Any creature that consumes the water, breathes it, or spends more than 1 minute in it must begin to make a Constitution saving throw every minute. If the creature succeeds on two of these saves, it automatically saves against this effect for the next 24 hours. If the creature fails two of these saves, it is afflicted by a disease that can last beyond the spell's duration. While diseased in this way, it is always poisoned, and it can't regain hit dice or reduce its exhaustion level by resting. It repeats the saving throw every 24 hours, ending the disease on a success, and taking 3d6 necrotic damage on a failure.

Since this spell induces natural diseases in creatures, any effect that removes a disease or otherwise ameliorates a disease’s effects apply to this spell's diseases.

At Higher Levels. When you cast this spell using a spell slot of 7th or 8th level, the duration of the spell increases to 30 days. When you cast this spell using a spell slot of 9th level, the duration increases to 1 year.