All About Water Spots

Those white marks we all see on shower glass, chrome tapware, vehicle windows and many other surfaces are usually Water Spots.

Magnified Water Spots

A water spot is simply dried minerals left behind when a water droplet has evaporated.

The types, quantity and combination of minerals in your water supply have a big effect on how severe water spots will be and will vary quite widely from region to region.  The most common minerals found in water are: silica, magnesium, calcium carbonate, copper, iron and lime.   These are naturally occurring, and perfectly healthy; they just aren’t very glass and hard surface “friendly”.

Water spots are also called:

  • Lime scale
  • Mineral deposits
  • Water stains
  • Etched glass
  • Water marks
  • Acid rain spots
  • Soap scum

Soap scum is not water spots.  Soap scum is simply soap residue, along with body fats and oils, left behind on a sink, bath or shower.  It just so happens that soap scum sticks to water spots more than clean surfaces.  If you can remove what appears to be a water spot build-up with a general purpose cleaner, say something as simple as a bit of dish wash liquid and warm water, then you only have soap scum.  If the spots are still there after a typical cleaning then you probably have water spots.


The best way to prevent water spots is to get the water off the surface immediately after you stop applying the water.  It stands to reason: if you get rid of the water you get rid of the minerals.

Towel Drying

If you dry the surface immediately with a towel, shammy or other absorbent cloth you are almost certain to avoid getting water spots, assuming you do a good job of it each time.  The minerals are absorbed with the water and they are gone – end of story. 


Running a squeegee over wet glass will definitely help reduce the build-up of water spots.  If you do a good job with a good quality squeegee (a rubber, rather than plastic, blade is essential) you’ll get most of the water off but it will still leave small amounts of moisture (and minerals) in the nooks-and-crannies.

To make either drying or squeegeeing effective you need to do it every time and you need to do a good job of it; the better the effort, the better the result.


Now days there are a range of protection options you can apply to glass, tiles and other hard surfaces to help protect them from water spots.

In 2004 we developed and introduced SHOWER SHIELD and many, many thousands of household, apartment, motel, hotel and timeshare showers (glass/tile/acrylic/fibreglass) have been protected with SHOWER SHIELD over the years.

SHOWER SHIELD is a cost effective do-it-yourself protectant that helps prevent water spots from occurring and makes cleaning so much easier.  We say it is a do-it-yourself product but we have commercial shower cleaner customers who use SHOWER SHIELD as part of the clean-and-protect process and recommend it to their customers.

SHOWER SHIELD is a genuine two-minute-task that you apply every month or so.  A 250ml bottle will allow you to protect your shower many, many times as one of the key application instructions is to “apply sparingly”.
Note to your average bloke:    Sparingly does not mean “If a little is good, a lot must be better”.

Alternatively, you can spend many hundreds of dollars to have someone come in and apply a so-called permanent protection to your shower.  Unfortunately, we have talked to a great number of rather disappointed punters over the past few years who spent a lot of money having their showers protected this way only to find out things like “... we still have to dry our shower every time we use it or the warranty is void...” (refer Towel Drying on this page) or that “...the shower simply hasn’t stayed clean like they said it would...” . 


If you already have water spots then your first task is to get rid of them.

C-thru Water Spot Remover is the first and original water spot removal product in New Zealand and is 100% New Zealand Made.  It is the sure-fire way to get rid of water spots without damaging your valuable glass, porcelain, tiles, stainless steel, chrome or other hard surface is with C-thru Water Spot Remover. 

You will undoubtedly have read somewhere on the internet or elsewhere that vinegar and warm water will get rid of lime scale and/or water spots.  Toothpaste and baking soda are two other common home-remedy type suggestions that keep going around.  To be fair, if you had very, very mild and new water spots then these types of suggestions might work for you but if you’ve got any real form of water spots then you need a professional grade product with proven results and a money-back guarantee to back it up.

Our recommendation:  get rid of the spots first then stop them from becoming a problem again.  Once you get a surface clean it is much easier to keep it clean.

MAKE SURE that whatever product you use that it is:

  • Guaranteed to get you the result you’re after;
  • SAFE to use.   C-thru Water Spot Remover is:
    • safe on your skin
    • safe around children
    • safe on the environment
    • safe in septic tanks
    • safe around animals
    • safe around plants
    • safe around food.

Many cream type cleansers and other water spots/water stain removers contain Known Human Carcinogens as classified by the International Agency for Research on Cancer The materials covered include: silica amorphous, crystalline silica (often in the form of quartz or diatomaceous earth), cristobalite and any other type of quartz silica material.

We’ll bet they don’t tell you that in their promotional information!

See for yourself...

The Finger Nail Test

You can FEEL water spots starting to build-up before you can see them and your finger nails are far more sensitive than your finger tips at feeling water spots.

The best example for comparison is a shower door, but this works on any surface:

  1. Start with what should be the water spot free side of a surface (inside of a car window, outside of a shower door, etc).  Turn your hand so that you are looking at your palm.  Push the opposite side (the back) of your hand back towards the top of the clean surface so that your finger nails make contact with the surface.  Slowly drag your finger nails down the surface and the entire areas should feel quite smooth.
  2. Repeat the above process on the opposite side of the surface (outside of a car window, inside of a shower door, etc).  If the surface is starting to develop water marks you will be able to feel the roughness or resistance as you drag your finger nails down or across the surface.

And then there are the WRONG ways…

Below are just some of the things people have used, out of desperation, trying to get rid of water spots.

Razor Blade:  We’ve seen numerous glass showers with scratch marks that, amazingly, are rather consistently spaced apart by about the exact width of a safety razor blade.  Now how coincidental is that?

Steel Wool:  Round coils of steel tend to be harder than glass, chrome, tiles and most other surfaces that develop water spots.  Swirling scratch marks tend to be the most noticed end result.

Scouring Pads:  Just the term “scouring pads” conjures up images of scratches and why would anyone expect anything less?  We know of one gentleman who had to replace five house windows after trying to get rid of water spots with a green scouring pad.

C-thru Water Spot Remover’s domestic pack includes 3 scratch-proof application pads.

Wet-n-Dry Sandpaper:  A rather bad idea when you consider that sand paper is basically designed to “scratch” one material off another.

Bleach: great at killing bacteria, including that on tile grout, but bleach will not dissolve or remove water spots, yet some people claim it does.  The smell is enough to put you off and bleach should NEVER be put into your toilet bowl; it’s hard on the porcelain (remember seeing a crazed pattern in older porcelain sinks when bleach was the primary household disinfectant/cleaner) and it is terrible on septic tanks and sewage systems.

The Wrong Chemical Cleaner:

  • Oven Cleaner - we struggle to see why someone would even think of trying to use oven cleaner to get rid of water spots (“desperate time = desperate measures...”). 
  • Paint Stripper - it might smell slightly less toxic than oven cleaner but there is nothing about this type of product to think it should remover water spots.
  • Floor Polish Remover - in the same category as paint stripper….
  • Hydrofluoric Acid - we know of one person who somehow managed to get hold of some of this rather toxic (deadly) and highly controlled substance.  It is fair to say this is one acid that will get rid of water spots.  HOWEVER, if it doesn’t kill you, or the fumes don’t permanently damage your lungs and the corneas of your eyes, you will still have to deal with the problem of horribly etched shower glass (assuming you rinsed the acid off before it completely dissolved the glass).

We’d love for you to contact us with any stories of weird and wonderful things you have tried, out of desperation, to get rid of water spots.

Available at these stores: Mitre 10, Bunnings Warehouse, Mitre 10 Mega. Also Available at selected outlets.