Breakdown of Si el inodoro sigue perdiendo agua, la fontanera revisará la cisterna esta tarde.
Questions & Answers about Si el inodoro sigue perdiendo agua, la fontanera revisará la cisterna esta tarde.
Because in Spanish, a real or possible future condition normally uses:
si + present indicative + future/main clause
So:
Si el inodoro sigue perdiendo agua, la fontanera revisará la cisterna.
This is the normal pattern for If the toilet keeps leaking, the plumber will check the tank.
English often uses the present after if too: If it keeps leaking, she will check it. So in this case Spanish and English work quite similarly.
You would not normally say si seguirá here, and si siga would also be wrong in this kind of straightforward condition.