Brisbane’s famous humidity is a drain fly’s dream – and your nightmare. These tiny, moth-like pests (aka drain bugs) breed in the slimy biofilm that coats pipes under every Queenslander, slab home and Southside unit. Left unchecked, a single blocked downpipe after a gumtree leaf dump can spawn hundreds overnight. So the obvious question as summer looms is: How to get rid of drain flies?
Here’s the 6-step S&J battle plan to kill the colony at its source – before your next backyard BBQ becomes a fly-by.
First, know thy enemy
Drain flies (Psychodidae) lay eggs in organic gunk:
- Hair
- Grease
- Food scraps
- Even the clay-rich silt that washes in from Brisbane’s red soils.
Larvae – those wriggling drain worms – feed for 7-14 days in the dark, moist film inside your pipes. Adults live just 2 weeks but emerge in waves. In our subtropical storms, one overlooked laundry trap can fuel a suburb-wide infestation.
Myth buster – Will vinegar kill drain flies?
Short answer: no. Pouring white vinegar down the sink feels satisfying, but it only disturbs adults. The acetic acid doesn’t penetrate the gelatinous biofilm where eggs hide. Same goes for straight bleach – it kills surface larvae but corrodes galvanised pipes common in pre-1980 Brisbane homes. So save the pantry staples for your fish and chips.
Your 6-step battle plan
Follow this Brisbane-tuned sequence to wipe out every life stage – from egg to adult – in under a week.
1. Locate every breeding zone
Start outside. Check:
- Stormwater grates
- Gutter downpipes
- The sub-floor void under high-set homes.
Inside, inspect every S-bend. That means:
- Bathroom basins
- Showers
- Laundry tubs
- Even the fridge drip tray.
How to get rid of drain flies in bathroom spaces? First, lift the plug – if the trap smells like a swamp, you’ve found ground zero.
2. Starve the larvae – Mechanical clean first
Grab a drain brush or $10 Bunnings drain snake. Scour the top 30cm of every waste – that’s where 90 percent of biofilm lives. In older ceramic pipes (common in West End terraces), use a wet/dry vac to suck out the sludge.
PRO TIP: Tape a stocking over the hose end to trap the gunk without clogging the vac.
3. Deploy the drain fly killer duo
- Mix 1:1 boiling water and bio-enzyme digester (look for “septic-safe” on the label).
- Pour 2 litres down each affected drain at night when flow is low.
Enzymes eat the organic film for 48 hours, and the boiling water flushes dead larvae. Repeat this nightly for 3 days for a solution that involves zero harsh chemicals and zero pipe damage.
4. Trap & monitor adults
Let’s make a DIY sticky trap:
- Smear petroleum jelly on bright yellow paper
- Hang it above the drain.
Drain flies are naturally drawn to yellow – and stick fast. Count corpses daily – numbers should drop 80 percent within 72 hours.
If you still have swarms, the colony must be deeper than DIY can reach.
5. CCTV the pipe – Brisbane’s secret weapon
Here’s where the locals really win. Brisbane’s clay-reactive soils crack pipes and trap debris in bellies invisible from above. Our CCTV drain cameras snake 40m to pinpoint root intrusion under the driveway or collapsed stormwater under the deck. One 15-minute inspection saves hours of guesswork.
6. Prevent round two – Brisbane-proof your pipes
- Install $8 mesh guards on all downpipe outlets (remember: gum-nuts are larva food).
- Every month, pour half a cup of bio-enzyme down the drain together with a kettle of boiling water.
- Pensioners can claim your 10 percent discount on annual maintenance plans.
- New build? Ensure backflow prevention is in the builder’s plans to stop sewage from refluxing into laundry traps.
When DIY isn’t enough
If you’ve scrubbed, enzymed and still see how to get rid of drain flies Australia trending in your nightmares, the nest is likely in a cracked pipe or council stormwater junction. And at S&J Plumbing and Gasfitting, that’s our cue to leap to your rescue.
Book a CCTV drain inspection today, because whether you’re in Brisbane Northside, Brisbane Southside, Logan, Moreton Bay, Redland Bay, or Ipswich, we’re usually there the same day! Call or click to book online – and don’t let drain flies crash another Brisbane summer.