Affirming denial of class certification in this case charging Folsom with a public and private nuisance of furnishing its customers with too acidic, chlorinated water that corroded copper pipes, the court holds that the trial court did not abuse its discretion in finding that individual questions as to liability predominated. Folsom’s own expert studies showed only that its water “could” have caused pin-hole leaks in copper pipes (about which there had been a surge in the number of complaints). Folsom’s litigation expert, whom the trial court properly held to be sufficiently qualified, testified that the pipe samples he examined showed leaks due to causes other than the acidic water. While individual issues as to damages only won’t prevent class certification, where, as here, individual class members would need to prove individual issues relating to liability, it was not an abuse of discretion to deny class certification.