Nine out of 10 backyard pools in Sydney fail safety tests.

Since Christmas Day, four children under five have drowned in NSW.  Three died in backyard pools and one in a backyard fish pond. Their names are: Aria Dunn (20-months), Vera Peacock (two years old) and twins Robbie and Charli Manago (23 months).

It’s sad beyond words.

Alison Mahony, Senior Research Officer with Royal Life Saving Australia says we’ve definitely seen a spike in backyard drowning deaths in NSW this summer.

“It’s concentrated over that Christmas/New Year holiday period. A lot of people are off work for Christmas, spending time outdoors and of course it’s school holidays. And over that particular period we saw the number was four or five times higher than the average over the last 10 years, just in NSW.”

Mahony says there are a number of contributing factors to explain the spike.

"I think that we had a period of really hot weather that coincided with that holiday period, but we saw a whole different range of people drowning. We saw quite a lot of toddlers drowning mostly in backyard pools."

Daily Telegraph reporter Kelly Burke has written about the drowning deaths, suggesting some councils have failed to perform random safety checks on pools and that is contributing to the issue. "As many as nine out of 10 backyard swimming pools in Sydney are failing safety inspections, with one council recording a noncompliance rate as high as 98 per cent."

That's nine out of 10 pools failing safety inspections.

Burke writes the information was obtained from "18 councils in the Sydney metropolitan area" and showed some councils prioritising checks and others doing minimal checks.

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Mahony from Royal Life Saving says the popularity of affordable inflatable pools has also contributed to the drowning deaths with a two-year-old dying in hospital in Brisbane, QLD in January this year after he was pulled unconscious from a blow-up pool.

"We've seen more families have inflatable pools or a wading pool and because they're so cheap to buy you wouldn't consider fencing."

But regulations require any pool that holds more than 30cms of water to be fenced so technically they should be as well.

83 children have drowned in backyard pools in NSW since 2003 and that doesn't include over 90 children left with brain damage after being rescued. This summer 18 people in total have drowned since Christmas Day.

Pool fencing requirements in NSW depend on when the pool was built and each state has its own set of rules. Pools built before 1990 don't require a pool fence to surround the pool, with back doors being able to form part of the barrier.

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Those built from 1991 pools require a fence that separates the house from the pool, unless it's a very small property, a very large property or a water-front home.

You can read more details about NSW pool fencing compliance through the Fair Trading website.

Mahony says the messages that will come out of this devastating holiday period will be around properly supervising children around water, avoiding alcohol around water and and being aware of your own fitness and abilities as well as medical issues before going out in the water.

"We want parents to be supervising their kids really closely, keeping them within arm's reach and avoid distractions, so whether that's the front door, a text message, email, it doesn't take long for a child to drown so they need your full attention without being distracted."

For more information on backyard pool fence compliance in your state visit one of the following websites:

NSW Fair Trading

KIDSAFE VIC

SA Law Handbook

TAS Consumer Affairs and Trading

WA Building Commission 

NT Government

QLD Building and Construction Commission