Anas RadhiAllahu anhu said, “The Prophet SallAllahu alaihi wasallam used to perform ghusl with a sa’a of water (1.616 cm3) 3 to 5 madd (each 4 madd equals one sa’a). He also used to make ablution with one madd (404 cm3) of water.”
(Bukhari and Muslim.)
……*One Sa’a is equivalent to 2.03 litres and five Madd is equivalent to 2.55 litres. One Madd is approximately 700ml. The least amount of water used by the Prophet SallAllahu alaihi wasallam mentioned in the hadith is 1/3 of a Madd, which is equivalent to 0.17 litres,..
…’Ubaidullah ibn Abu Yazid narrated that a man asked Ibn ‘Abbas RadhiAllahu anhu, “How much water is sufficient for wudhu?” He answered, “One madd.” “And how much is sufficient for ghusl?” He said, “One sa’a.” The man said, “That is not sufficient for me.” “Ibn ‘Abbas said, “No? It was sufficient for one better than you, the Messenger of Allah, SallAllahu alaihi wasallam”
(Related by Ahmad, al-Bazaar and at-Tabarani in al-Kabeer)
of course one needs to take into account the availability and cost/effort of obtaining water in their area, if it's plentiful, why not lather, scrub, soap and wash? being careful of ocd of course. cleanliness is of faith.