My watertank has a very small hole in it about 3 qts of the way up, it is like a small pin prick, you can see the water coming out, will it have to be replaced or can it be fixed?

If I am on the wrong forum, can a mod please change it. Thanks.

What kind of material is it?

Sounds like an easy fix to me.

14 minutes ago, jvs said:

What kind of material is it?

Sounds like an easy fix to me.

It is metal, one of these watertanks that cost about 14,000 Baht, this one is about 14 years old.

About 6 years ago one of our stainless steel tanks, then 10 years old, developed a couple of leaks as a result of degradation due to welding damage at time of install. I drained below the holes, applied PU sealant and a thin metal sheet patch fixed with alloy wire wrapped around the tank.

It could be welded.  It's probably stainless steel.  Might be hard to find someone who's truly qualified.  In all likelihood there are many spots on the verge of breaking through, but sometimes not.  You have to patch it on the inside assuming that's accessible.  I'd first try something like Flex Tape.  I see it on Lazada and Shopee (4 inch).  Clean the area with something like hand sanitizer and some sandpaper if it's rough.  

 

The best option is replacement, but always more costly.

 

For a quick temporary repair gently hammer a wooden toothpick into the hole. The toothpick will expand and fix the leak for a few days while you sort out a better repair.

I think you can get adhesive repair patches for water tanks.

Mark the hole, then drain the tank to below that level.

A bit of two-pack epoxy or silicone sealant is probably all that is needed.

Or just lower the float valve and use the good 3/4 of the tank.  If you are in a coastal area probably better to just change to plastic tank when the time comes.  As mentioned if one leak there are likely others developing.

11 hours ago, lopburi3 said:

Or just lower the float valve and use the good 3/4 of the tank.  If you are in a coastal area probably better to just change to plastic tank when the time comes.  As mentioned if one leak there are likely others developing.

It depends on what kind of metal the tank is, which the OP does not specify.

Very unlikely with stainless, quite probable with a galvanized tank as the sacrificial protection of the zinc fails.

An old trick to prolong galvanized tank life is throwing a couple of chunks of concrete into the tank, thereby raising the Langelier index, and promoting scaling.

37 minutes ago, Lacessit said:

It depends on what kind of metal the tank is, which the OP does not specify.

Very unlikely with stainless, quite probable with a galvanized tank as the sacrificial protection of the zinc fails.

An old trick to prolong galvanized tank life is throwing a couple of chunks of concrete into the tank, thereby raising the Langelier index, and promoting scaling.

At a price of 14k I would hope it would be SS and it is indeed possible for corrosion of such tanks from salt air, even when good quality, which many are not.

4 hours ago, lopburi3 said:

At a price of 14k I would hope it would be SS and it is indeed possible for corrosion of such tanks from salt air, even when good quality, which many are not.

The pin holes are usually from improper welding techniques rather than poor quality stainless steel so most likely the tank is far from end of life 

5 hours ago, lopburi3 said:

At a price of 14k I would hope it would be SS and it is indeed possible for corrosion of such tanks from salt air, even when good quality, which many are not.

IIRC stress corrosion cracking of stainless requires a temperature of 60 C to take place.

Pinholes are another matter, either related to poor quality SS or, as another poster has suggested, corrosion at a weld boundary.

18 hours ago, Lacessit said:

Mark the hole, then drain the tank to below that level.

A bit of two-pack epoxy or silicone sealant is probably all that is needed.

Get a self tapping screw bigger than the hole and a bit of old innertube for a washer. Slap some epoxy onto the screw and rubber and screw the screw in tight. Will last a lot longer than considering your next plan.

 

If there is one hole there are likely more in the making which can be fixed in the same way.