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Where does hydrovac slurry go in Waterloo? The Region's disposal rules, and why a catch basin is out

Hydrovac slurry from a Waterloo job leaves in the truck and goes to a receiving facility set up to take it. It cannot go into a catch basin, a manhole or the sanitary sewer under the Region of Waterloo's Sewer Use By-law 21-036, and once it is off site it is excess soil under Ontario's rules. Here is what that means in practice.

Last updated October 24, 2026 · Reviewed by the Waterloo Hydrovac team

Can hydrovac slurry go down a catch basin?

No. A catch basin drains to the storm sewer, and the Region of Waterloo's Sewer Use By-law 21-036 allows matter to be discharged to a storm sewer only if it is uncontaminated cooling water, storm water or uncontaminated water. The by-law defines storm water as water from rain or melted snow and ice, and uncontaminated water as water with nothing added to it as a result of its use. A tank of wet soil with whatever was in the ground mixed through it is neither, and the by-law also requires that any storm sewer discharge not obstruct the sewer or impair water quality in natural water bodies. Waterloo's storm sewers drain toward Laurel Creek and the Grand River system, so a slurry dump in a parking lot basin is a sediment load headed for a watercourse, and the by-law treats it as a prohibited discharge.

Why the sanitary sewer is not an option either

The sanitary sewer has numeric limits, and slurry fails the first one. The by-law sets a total suspended solids limit of 350 mg/L for discharges to the sanitary sewer; hydrovac slurry is mostly solids by weight and exceeds that by orders of magnitude. The by-law also prohibits solid or viscous matter in quantities or sizes capable of causing an obstruction. The permit route does not help: the by-law's Temporary Discharge Permit may be issued for temporary de-watering related to construction on the operator's own property, and only where there are no other reasonable disposal options. Soil has another disposal option, which is hauling it, so the permit was never meant for spoil. On campus and institutional sites in the University District the owner's own environmental requirements are usually stricter again.

Slurry is excess soil once it leaves the site

Ontario regulates soil that is dug up and moved off a site under O. Reg. 406/19, the On-Site and Excess Soil Management regulation. The province defines excess soil as soil that has been dug up, typically during construction, and must be moved off site because it cannot or will not be reused there, which describes every tank of hydrovac spoil. The regulation sets out when excess soil is not a waste and what a reuse site must do to receive it, with registration and tracking requirements for larger reuse sites and stricter planning for soil from riskier sources such as gas stations and industrial sites. Soil from a Lakeshore back yard and soil from a former industrial lot are not the same material in the eyes of the regulation, which is one reason an operator asks about site history before quoting disposal. From 2027 the province also restricts landfilling cleaner soil that is suitable for reuse, so the pressure to send clean spoil to a reuse site rather than a landfill is increasing.

Where the spoil actually goes

Hydrovac slurry is wet, and most receiving sites want solids. The usual path is a facility that accepts slurry and dewaters it, after which the solids go for reuse or disposal under the excess soil rules and the water is handled under the facility's own approvals. Which facility depends on what is in the tank: clean native till from a Laurelwood fence line is the easy case, while spoil from a paved commercial lot or a site with an industrial past may need testing and a facility approved for potentially contaminated soil.

The Region of Waterloo's own waste sites are part of the picture for solids but not for liquid. The Region's Waterloo Waste Management site at 925 Erb Street West lists soil and clean fill among the materials it accepts, only for waste generated within Waterloo Region, and charges mixed loads at the highest applicable rate. Liquids and sludge are not on its accepted list, so a hydrovac tank is not tipped there as it comes off the job. That is the operator's problem to solve, not the customer's, but it explains why disposal is its own line on a quote and why the number of loads is estimated rather than guessed.

What a Waterloo customer should expect to see

Disposal as a separate line. Per load or per tonne, with the expected number of loads for the hole count, depth and soil on your site.
A question about site history. Former fuel storage, an industrial tenant or a paved yard changes the receiving facility and the price.
Backfill brought in. Holes are backfilled with clean granular material and compacted rather than refilled with slurry, which would settle.
No discharge on site. Not into a catch basin, a manhole, a swale or a ditch. An operator who proposes it is proposing a by-law contravention on your property.
Records if you need them. Institutional and commercial owners can ask where the spoil went, and a straight operator can tell them.

The catch basin cleaning service follows the same rule in reverse: the sediment vacuumed out of a basin is hauled away, not jetted down the pipe to become the next blockage or the river's problem.

What this means for your quote

Clay and till produce heavy, wet slurry, so a day of deep holes on the west side fills the tank faster than the same count in sandy ground, and the disposal loads follow. A quote that leaves disposal out, or rolls it into the hourly rate, has guessed on your behalf. The Waterloo hydrovac cost page sets out how loads are estimated and what moves them. If your site has a history worth mentioning, say so when you describe the job, and the operator will quote the right receiving facility from the start.

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