Now Brent Riach fears the situation will get worse when Orange Anglican Grammar demolishes a home opposite the Riach’s to make way for a new sports oval.

Orange City Council approved the development earlier this year despite objections from the family.

Mr Riach said problems started when the school was built and he believes there wasn’t enough drainage established.

“The stormwater all came along our property and eroded the entire front and even under the road base,” he said.

According to the development application (DA) a stormwater detention basin near the entrance of the school will be removed and the oval itself will become a detention basin.

Mr Riach is concerned the new oval will direct even more water down to the property and could even carry toxic soil contaminated from chemicals used at the site’s former orchard.

“It says [in the DA] chemicals that are probably there from the orchard could include arsenic, lead, and DDT,” he said.

“But they haven’t done any soil samples. With the amount of water on there they’ll lose tonnes and tonnes of soil.

“With the amount of water they could collect in the retention basin they could use it for irrigation.”

Council spokesman Nick Redmond said staff had completed work to redirect water from the culvert in front of the Riach’s property to an alternate stormwater rock chute along the side boundary of the property to the creek.

He said the raised oval would improve drainage in the area when it becomes a detention basin and soil was unlikely to run-off during construction.

“We’ve done it with a lot of sportsgrounds around town and it stops the run-off,” he said.

“When you do constructions you have to comply with all sorts of regulations.

“The run-off from the school site will stay on the school side of the road.”

But Mr Riach said water was still washing silt and mud into the front of his property and the erosion had continued despite the recent council work.

Rain last week worsened the problem covering gravel in the drain with more soil, Mr Riach said.

“The water puts a lot of silt and pebbles into our property,” he said.

“The dam at the bottom is filled with silt. A pine tree is dying off because there’s too much water.”

Mr Redmond said there would always be some water running off the road during storms.

The school’s principal Ann Brown declined to comment.