Landlord not cleaning the water tank of the home we are renting

We, family of 3 are slowly shifting into a new rented accomodation in a building nearby.

my mother went there a few weeks back to see the place for the first time. Me and my dad chose this place because of how large it is.

So, my mom checked the 'maala' and over there... there was this cramped, musty room where the water tank was seated.

she opened the lid of the tank and the water was muddy and had tiny cobwebs from the top of the tank. My mom told my father and ne about this.

Me and dad no idea the tank was like this because the time we visited the place there was someone sleeping on the maala. I felt weird to go up there. The ladder was very steep and scared the shit outta me.

We tried calling up the landlord several times telling him about this— he would always say he is busy and he didnt have the time to come. Each time my father called him he had some or the other reason.

Mind you the landlord stays five minutes away from the new rented accomodation we bought. He also has his own business (so maybe he wasnt always lying— he was really busy).

Fast forward today: he came today to visit us. we hadnt moved in permanently. we still have lots of shifting to do— cupboards, bed, steel tank, my desktop setup, cooking stove, etc.

my mom asked him how to use the knobs in the bathroom asking which connection is from where. then they went upstairs. the watertank there she showed him was muddy and had thick brown stuff in it. he had the audaicty to say the brown stuff was very little.

i said it on hia face that the mud was coating the base of the tank. my mom then asked him whether he will be cleaning it for us and he said he wont be doing it. he will give the plumber's number and we will have to bear the expenses.

we paid i think around 30k rent for this room around with a 1 lakh deposit (not sure about this) and my mom told us as we went home that if he's charging us so much he should at least do the cleaning..

the water from the tap has a funny smell. the bldg BMC tank isnt like this. this is the first time we are actually using a tank. in my current home, we get water at a specific time and we boil all the water we drink.

my mom feels he is very firm in what he said and wouldnt budge. i feel we were scammed out of this. i realized now that the previous tenants put a seive like cloth around the tap and used it.

as a new tenant who has NEVER lived in a rented accomodation, what can be done? my dad is telling my mom not to get into this by forcing him to get someone and clean it. he fears our landlord may tell us to leave.