Skip to content
Call us on (02) 9986 2126
Call us on (02) 9986 2126

Wet & Forget Concentrate 5L - Exterior Moss & Mould Remover

Find a store

The original Wet & Forget concentrate is the ultimate outdoor moss, mould, lichen and algae remover that is safe to use on any exterior surface. It kills problem spores and helps stop premature regrowth of unwanted biological growth.

How it works

The original Wet & Forget concentrate has a unique combination of biodegradable selective fungicides to target moss, mould, lichen, algae, and general biological growth. When diluted with water and applied to a dry surface, it immediately attacks the growth. These fungicides work in conjunction with a carefully selected range of surfactants to help loosen and lift biological growth, and then Mother Nature takes over. The weathering process gently removes the decomposing growth over time without damaging the surface it has infested.

Scroll down for more information.


Wet & Forget concentrate:

  • Is non-caustic, non-acidic and bleach free.
  • Is an easy, do-it-yourself application.
  • Requires no scrubbing or water blasting.
  • Has a pH of 8 (Water has a pH of 7).
  • Is biodegradable.
  • Dilutes into your garden sprayer.
  • 5L bottle covers a minimum of 100sq metres (it makes 30L of product).
  • Has an unlimited shelf life both in its concentrate form and when made up in a garden sprayer.
  • Kills problem spores at the source and helps prevent premature regrowth.
  • Smart Approved WaterMark (certified as a water efficient product in Australia).


How to apply Wet & Forget

  • Sweep all leaves, dirt and other debris off the surface before application to allow for maximum penetration of the active ingredients. 
  • Dilute one part Wet & Forget to five parts water (1:5) in a garden or backpack sprayer. 
  • Spray the affected area to the point of saturation. Do not hose off. 
  • Apply during overcast, dry conditions to avoid accelerated evaporation. 
  • Do not apply if rain is expected in the next 12 hours. 
  • Lichen requires a second application within 15-20 minutes of the first. 
  • Keep children and pets off the treated surface until dry (normally 1-2 hours).
  • If badly contaminated, apply a second application one month after the first. 

When to expect results with Wet & Forget

  • Algae will disappear within days. 
  • Moss will turn brown within a few days and other light growth will decompose within a few weeks. 
  • Black mould will noticeably improve within 4-6 months, however if the area is heavily contaminated it will take 6-12 months. 
  • Lichen requires two applications within 15-20 minutes of each other and will take 8-12 months to decompose. 

Note: It is normal for some treated surfaces to turn an orange/brown colour after application. This discolouration indicates a good result, however it is not permanent and will soon disappear. 

Wet & Forget PPE

While Wet & Forget is a gentle cleaner, the use of protective equipment is still recommended when applying it to your surface.

When applying Wet & Forget, please consider using the following equipment:

Safety Information


Please note:

  • Wet & Forget is not an instant product as it relies on the weather to help decompose the dead growth.
  • You cannot use the original Wet & Forget concentrate (blue) with the Rapid Application hose-end nozzle (pink). It will not work as the dilution rates are different!

Wet & Forget PPE

While Wet & Forget is a gentle cleaner, the use of protective equipment is still recommended when applying it to your surface.

When applying Wet & Forget, please consider using the following equipment:

Safety Information

Learn more from our Blog posts about Wet & Forget


Wet & Forget can be used to treat the following surfaces. Wet & Forget is suitable on any exterior surface, however if you do not see your surface listed here and you are unsure, please do not hesitate to contact us.

  • Asphalt
  • Awnings
  • Boats
  • Bricks
  • Canvas
  • Caravans and awnings
  • Ceramic pots
  • Clay and concrete tiles
  • Colorbond roofs
  • Concrete
  • Decks
  • Driveways
  • Fibreglass
  • Fibrolite cladding
  • Glasshouses
  • Golf and bowling greens
  • Gutters
  • Inflatable dinghies
  • Limestone
  • Marble
  • Moss in lawns
  • Outdoor furniture
  • Outdoor umbrellas
  • Paintwork
  • Paths
  • Patios
  • Pavers
  • Pergolas
  • Polycarbonate roofs
  • Pool surrounds
  • Sandstone
  • Shade sails
  • Stenciled driveways
  • Stonework
  • Synthetic grass
  • Tennis courts
  • Terracotta roofs
  • Textured finishes
  • Tiles
  • Tombstones
  • Weatherboards
  • Yacht dodgers and sails
  • And more!

Frequently Asked Questions

  • If I am on tank water, can I use Wet & Forget on my roof?

    You sure can, however you must disconnect the water supply to your tank for at least 10mm of rain or 2 good downpours to remove the concentrate. Wet & Forget has been used for over 25 years to treat biological growth on roofs.

  • How much Wet & Forget will I need to clean my roof?

    The average 3 bedroom tile roof is approx 150 sq metres, because of the undulations of the tile profile the actual area is a lot bigger. Therefore an average tile/concrete roof would require 2 x 5 litre bottles, depending on how porous the surface is and how much biological growth is present. For an average 3 bedroom tile roof with lichen you would require 3 x 5 litre bottles depending on the total area covered with lichen. For best results mix the Wet & Forget and spot spray the lichen, leave for 15 minutes and then respray the lichen and the entire roof to ensure the lichen absorbs the Wet & Forget thoroughly. The first application is to dissolve the waxy surface and the 2nd spray will then penetrate the lichen. For green moss and black mould one application is normally sufficient. Your roof will normally take between 6-12 months to come clean.

  • Will Wet & Forget affect my pets?

    Keep your animals off the treated surface until the product is dry to ensure that they don’t lick any of the product. If they accidentally walk or sit in the product before it dries, wash the affected areas with fresh water as a precaution.

  • Will Wet & Forget damage my plants?

    Wet & Forget is okay to use around plants provided certain protective steps are taken. When spraying the product near plants, make sure to either cover them with a tarpaulin (or something similar) or alternatively, wash the plants down with water before and after applying the product nearby. The leaves of the plant may experience a slight discolouration or spot burn if they come into contact with the product for an extended period.

  • Can I change the specified ratios given in the instructions for Wet & Forget?

    Yes. If the contamination is extreme, increase the strength or apply a second application a month after the first. However, if you have cleaned the surface previously with Wet & Forget and you want to give it just a maintenance spray, you can decrease the strength if the contamination is light. The cleaning process will still be just as effective.

  • Do I have to apply Wet & Forget all at once?

    You don't have to spray the entire area at once, just remember where you have stopped and started. The product is fine if left in the spray container as it does not deteriorate when it has been diluted. It will not damage your garden sprayer as it is not corrosive.

  • How often do I need to apply Wet & Forget?

    After the initial application, Wet & Forget only needs to be used for maintenance. Apply at the first sign of regrowth to avoid the need for a large scale application.

  • What is the shelf life of Wet & Forget?

    Wet & Forget has an unlimited shelf life. Always keep the cap done up tightly and the container out of reach of children.

  • What is the dilution rate and coverage of Wet & Forget?

    Dilute Wet & Forget 1:5 (1 part Wet & Forget to 5 parts water). Every 5L bottle makes 30L of product to spray. The coverage is between 100-300 sq metres depending on the porosity of the surface and the level of contamination, i.e. painted surfaces will use less product but porous surfaces readily absorb the product and therefore coverage could be in the range of 100-150 sq metres.

  • Can I use Wet & Forget around my pool?

    Yes it is fine to use on your pool surrounds. It is best applied in the coolest part of the day when the surface is dry. If you accidently get run off into the pool it won't alter the pool water balance.

  • Will Wet & Forget remove the mould off my timber deck?

    Most definitely! However if your deck is older and has never been cleaned, it may be noticeably blackened with the contamination. In this case, we recommend to wait a month after the application and give the area a light brush with a broom or scrubbing brush with warm water to help remove the dead growth. The good news is that you should only have to do this once and then the maintenance is easy.

  • Will Wet & Forget get moss out of lawns?

    Sure will! Firstly, lightly water the lawn but not enough to saturate the moss. Do this late in the day when the sun is low so that evaporation is kept to a minimum. Dilute the Wet & Forget 1:7 (1 part Wet & Forget to 7 parts water) and spot spray the moss. You may have to give it a couple of goes until you have it under control. At worst you may get slight burning on the grass but it will recover very quickly. Rake the dead moss out, then sprinkle lime over the area as this is usually a sign that your pH of the soil is not quite right.

  • If I have just applied Wet & Forget, am I able to paint or seal the area?

    You must wait until all the mould has decomposed before you can paint or seal the area.

An informative video on how to use and apply Wet & Forget Original Moss and Mould Remover.

See Wet & Forget Moss and Mould Remover in action with Dani and Walt on Healthy Homes Australia.

See Wet & Forget Moss and Mould Remover in action with Graham Ross as he applies it to his own outdoor area.


"After years of cleaning the ceiling of my double carport with sugar soap and bleach and having to use gloves, a stepladder and sponges etc. I decided to use Wet & Forget and to spray the ceiling with water a few times after it dried. Within a week the main ceiling was free of all the dirt and gunk except for the ceiling above a fountain,but within another two weeks the whole ceiling was as white as new. WHAT A WONDERFUL PRODUCT no more back breaking cleaning chores for me. Thank you for supplying this product to the public."

- H.Oliver

My personal affirmation of the success of the "Wet & Forget' product that 2GB advertises. My elderly parents live on the South Coast where they have a problem with green and slippery paths in their back gardens. Both need walking sticks, so slippery paths like this are extremely dangerous - when visiting I brought down my Wet & Forget bottle and within days the algae had died and completely disappeared within the week - and remains so. They were extremely impressed with the product and I was extremely grateful to avoid any potential accidents.

- Sharon

After removal of 41 years worth of accumulated lichen, it is like having a new roof.
I'll be recommending your product to several friends who have similar problems on their roof.

- Bruce

Hi Guys- just wanted to provide you some positive feedback on Wet & Forget. I treated backyard pavers in June and noticed a difference after first couple of months. Now the pavers look as good as new. In addition I treated some garden wall bricks. Bottom layer was filthy with algae and mould growth and top relatively new. Now its hard to tell the difference with whole wall looking new. I still have a container left and will be treating the concrete drive in next few days. Thanks again for such a good product.

- R Andrew Bishop

We cleaned up our family graves in the Nimbin Cemetery with “Wet & Forget”. Prior to using “Wet & Forget” the graves were as black as those in the background. Our family graves go back 60 years. We are absolutely delighted with how “Wet & Forget” cleaned up our family graves. Thank you for supplying such a wonderful product.

- Norm and Bernice
Wet & Forget used to treat growth on pool pavers.
Wet & Forget used to treat lichen on a terracotta tile roof.
Wet & Forget used to treat growth on sandstone pavers.
Wet & Forget used to treat green growth on a canvas awning.
Wet & Forget used to treat growth on pavers.
Wet & Forget used to treat green growth on a concrete side path.
Wet & Forget used to treat green growth on a timber fence.
Wet & Forget used to treat growth on a concrete urn.
Wet & Forget used to treat growth on a brick archway.
Wet & Forget used to treat growth on a brick wall.
Wet & Forget used to treat growth on patio paving.
Wet & Forget used to treat growth on a gravestone.
Wet & Forget used to treat growth on a garden pathway.
Wet & Forget used to treat growth on a headstone.
Wet & Forget used to treat a gravestone.
Wet & Forget used to treat growth on sandstone flagging.
Wet & Forget used to treat green growth on courtyard pavers.
Back to top