‘Not to be messed with’: Deadly find in NSW family’s swimming pool

A NSW woman has made a horror discovery in her swimming pool and is now warning others why they should check the water before diving in.

A NSW woman who discovered four venomous spiders in her swimming pool is now warning others why they should check the water before diving in.

Lynda Smith, who lives on the NSW north coast, said she recently spotted at least four eastern mouse spiders — similar to funnel-web spiders in appearance and venom — at the bottom of her pool after a bout of heavy rain.

According to experts, some of the state’s most venomous species capable of living for up to 30 hours under the water and therefore shouldn’t be assumed dead simply because they’re submerged.

“Please always check your pools before jumping in especially after rain,” Ms Smith warned on Facebook.

“We haven’t had any for a while, but all the rain we’ve had up here of late has obviously resurrected them.

“Not to be messed with.”

Lynda Smith found four mouse spiders in her NSW pool. Picture: Lynda Smith.

Lynda Smith warns residents to check before they swim – because the critters can live underwater for hours. Picture: Lynda Smith.

Australian Museum arachnology collection manager Helen Smith told 7NEWS.com.au: “Spiders do not breathe in the same way as we do, so it takes much longer for them to drown.

“They can survive for several hours and sometimes a thoroughly dead-looking spider can suddenly twitch or come back to life slowly.”

Ms Smith said mouse spiders and funnel-web spiders have the ability to bite underwater.

“But to bite they need to grip onto something — so don’t poke them,” she added.

Insects commonly fall into pools by accident, according to the Australian Museum.

“Wandering (mouse and) funnel-web spiders often fall into backyard swimming pools and they can stay alive for hours,” the museum’s site advises.

“They can’t swim but they can trap a small bubble of air in hairs around the abdomen, which aids both breathing and floating, so it should not be assumed that a spider on a pool bottom has drowned.

“As they gradually get waterlogged, their buoyancy decreases and they eventually sink and drown.”