Prayed with Tayammum and then found water
28-1-2014 | IslamWeb
Question:
What is the Sharee‘ah ruling if one prayed with Tayammum (dry ablution) and then he found water for Wudhoo’ (ablution)?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.
A person who prayed with Tayammum because he did not find water and then he found water after the expiry of the prayer's fixed time is not required to make up the prayer. The scholars unanimously agree on this, as Ibn Qudaamah 
transmitted in Al-Mughni. But what is the ruling if he found water before expiry of the prayer's fixed time? The preponderant opinion is that he is not required to make it up. This is the opinion of Maalik, Ahmad and Ash-Shaafi‘i 
. Another group of the scholars of Fiqh is of the view that he has to make up the prayer and that he will receive the reward twice for this. Abu Sa‘eed Al-Khudri 
narrated that two persons set out on a journey. Meanwhile the time of prayer came and they had no water. They performed Tayammum with clean earth and prayed. Later on they found water within the time of prayer. One of them repeated the Wudhoo’ and prayer but the other did not repeat. Then they came to the Prophet, sallallaahu ‘alayhi wa sallam, and related the matter to him. Addressing himself to the one who did not repeat, he said: “You followed the Sunnah (model behavior of the Prophet) and your prayer was enough for you.” He said to the one who repeated: “For you there is double reward.” [Abu Daawood, An-Nasaa’i and Ibn Maajah. Saheeh Hadeeth]
Allaah Knows best.