Domestic wastewater overflows

Wastewater spills need to be cleaned up as soon as possible.  Wastewater, whether sewage (combined solid and liquid waste) or effluent (liquid waste), contains organisms that can cause a risk to your health.

Who is responsible?

This fact sheet is for residents responsible for the clean-up of an overflow.

• A professional cleaning contractor may be engaged where required.

If your wastewater service provider is responsible for the overflow, contact them to discuss the clean-up process.

Before you begin

• Assume that any surface or material that has touched wastewater is contaminated.
• Keep children and pets away from wastewater and contaminated surfaces.
• Turn off electrical power in any flooded areas where there is a chance of electrical components, cords or fixtures coming into contact with wet materials or pooled water.
  • Contact a licenced electrician for advice
• Contact your insurance company for advice on making a claim. 
  • An assessment may need to be undertaken, to determine which items require repair or replacement
• Engage a licenced waste transporter to arrange the pump out of excess wastewater, if necessary.
• Arrange for a skip bin to be delivered, if necessary.

Prepare your supplies

• Supplies needed may include:
  • Hot water and detergent
  • Chemical disinfectant (usually containing an active ingredient of 1% quaternary ammonium compound)
  • Rags / cloths / sponges
  • Buckets / mops
  • Rubbish bags
  • Liquid or granular chlorine
  • Fans for drying

Protect yourself

• Cover any cuts, scratches or broken skin with a bandage or waterproof dressing.
• Avoid contact with wastewater and aerosols by using personal protective equipment:
  • Disposable protective coveralls
  • Long pants and long shirt
  • Boots
  • Rubber gloves
  • Face mask and safety glasses

Indoor cleaning

Following the removal of excess wastewater by a licenced waste transporter, consider what can be cleaned, and what might need to be discarded.

Carpets and rugs

• Saturated carpets, underlay and rugs are difficult to clean, and should be discarded unless able to be properly cleaned and disinfected by a professional carpet cleaning company.

Upholstered furniture, mattresses, and stuffed toys

• These items are unable to be effectively cleaned and disinfected, and are required to be disposed of. 
  • The absorbent nature will draw water in, and organisms will continue to grow
  • Very lightly contaminated items may be cleaned and disinfected by a professional cleaning company only

Bedding and linen

• Bedding and linen must be able to be effectively cleaned, disinfected and dried in order to keep.

Hard surfaces

• Wood, concrete, hardwood floors and metal furniture must be cleaned with clean hot water and detergent.

Vinyl or tiled flooring

• Vinyl and tiled floor surfaces typically do not absorb water.  These surfaces should be cleaned and disinfected, and then examined for any migration of water to cracks, joins or edges.
  • If water has infiltrated the surface below the floor, the floor covering will need to be removed for cleaning and re-instating, or replaced

Plaster products

• Plaster / plaster boards that are soft to the touch should be cleaned and disinfected. 
  • Where moisture remains after attempts to dry, they should be removed for disposal, and replaced

Appliances

• Where appliances have come into contact with wastewater, a licenced electrician must advise on the safety of their use.
  • Any salvageable appliances must be cleaned and disinfected

Outdoor cleaning

Following the removal of excess wastewater by a licenced waste transporter, consider what can be cleaned, and what might need to be discarded.

Exposure to the sun’s ultraviolet rays will assist in destroying disease-causing organisms.

Avoid contact with areas and items for at least 24hrs after cleaning / disinfecting.

Hard surfaces

• Bricks, pavers, concrete and other hard surfaces must be washed with clean water and a chemical disinfectant.
  • Water used for cleaning must be disposed of onto the property land to soak away (e.g., garden bed, lawned area).  It must not be directed to the stormwater system

Vegetated areas and plants

• Wastewater may be neutralised by builder’s lime mixed into soil.
  • This is not necessary in all cases, but will help to alleviate odours.
• Clean fill soil may be spread over soil and/or grassed areas.
• Plants may be gently watered with clean water and left untouched for 2 to 3 days

Animal beds and enclosures

Remove pets away from contaminated surfaces before cleaning.

• Discard any bedding and soft toys that cannot be effectively cleaned, disinfected and dried.
• Clean and disinfect food and water bowls.
  • Remove any food that may have been contaminated by wastewater.
• Clean and disinfect hard-surface enclosures, allowing to dry before returning your pets.

Sports equipment, toys and other hardware

• Items must be washed with warm water and detergent, and then disinfected and allowed to dry before use.
  • Where an item cannot be soaked in disinfectant (e.g., power tools), spray a lightly with disinfectant and then dry with a clean cloth.

Fish ponds

• Wastewater will generally not harm fish.
  • If the volume of wastewater entering the pond is significant, remove the fish and partially replace water with dechlorinated clean water.
  • Avoid contact with the pond for at least 2-3 days.

Home-grown fruit and vegetables

Fruit and vegetables that have had contact with wastewater are likely to be contaminated with disease-causing organisms.

• Discarding contaminated fruits and vegetables is the safest option.
  • Contact your local council for further advice on food safety

Swimming pools

There are two options for cleaning contaminated swimming pools.

Option 1

• Empty, clean and re-fill the pool.
  • Ensure emptied water is not directed to the stormwater system

Option 2

• Remove all visible material with a scoop.
• Add a flocculant or clarifier, dispersing and mixing it over the entire pool.
• Turn the filter off for 8 hours, to allow for solid materials to settle to the bottom of the pool.
• Vacuum settled materials to waste (not via the filter).
• Backwash the filter.

• Super chlorinate the water at 10 milligrams per litre (maintained), for >24hrs, by adding:

  • >14grams of granular chlorine (75%) per 1000 litres of water.

  • >80 milligrams of liquid chlorine (13%) per 1000 litres of water.

This should meet the minimum concentration and time value to super chlorinate an un-stabilised pool.

Stabilised pools should be circulated for >52hrs (at 10mg/l chlorine) or maintained at 20 milligrams per litre and circulated for >24 hrs.

Routinely check the concentration of chlorine throughout the super chlorination process and add the required dosage to maintain desired level.

• Check the pH level is 7.2 – 7.6, adjusting if necessary.
• Operate the filter for 24 hours.
• Backwash the filter.
• Ensure that the water is clear and chlorine level is between 1 to 5 milligrams per litre prior to pool use.
• Repeat the flocculation process if the water is still turbid (cloudy).

Preventing mould growth

Mould growth is likely when materials and surfaces remain wet.

• Items exposed to wastewater must be able to be effectively cleaned, disinfected and dried.
  • Items should be disposed of when this cannot be achieved.
• Keep areas well ventilated after the clean-up, to assist with drying.
  • Keep windows and doors open
  • Use fans to aid with drying where available