Is nuisance a legal characterization rather than trespass?

In Grace v. Fort Erie, supra, the plaintiffs alleged that the discharge of contaminated water, which reached the properties of the plaintiffs through a water distribution system operated by the City, caused damage to their sinks and clothing and constituted a trespass. In Grace v. Fort Erie, supra, the court held that nuisance was a preferable legal characterization rather than trespass and analyzed the criteria for certification on that basis.