With accent marks:
Вода́ ка́мень то́чит.
Water wears away a stone.
Even if you act with little effort but constantly and persistently, you can achieve a lot.
The English equivalents of this Russian proverb are: Little strokes fell great oaks, Drop by drop the sea is drained, Water dripping day by day wears the hardest rock away, Water breaks down a mountain.
Other Russian proverbs
Hurry to much and you will make people laugh.
Water does not flow under a lying stone.
Get your sleigh ready in summer and your (horse-drawn) cart in winter.
Your own shirt is closer to your body.
The best is the enemy of the good.
You can't command to the heart.
In a quiet whirlpool, demons live.
Repetition is the mother of learning.