If the street the defendant was required to keep in a reasonably safe condition for the use of travellers had become defective and dangerous by the decayed condition of the wooden box sewer, which was located about two feet below the surface, the city, if by the exercise of reasonable diligence it should have known of the defect, would be liable to the plaintiff whose due care is not questioned. In the exercise of reasonable diligence, on want of which the liability of cities and towns is made to depend under R. L. c. 51, §§ 1, 18, where it appears that natural causes are known, or from information ought to be recognized as in operation from the method of construction, and which probably will render the way unsafe, the duty devolves upon the municipality to take every suitable precaution to guard against the danger. Olson v. Worcester, 142 Mass. 536, 537. Fleming v. Springfield, 154 Mass. 520. Campbell v. Boston, 189 *109Mass. 7. But where neither from the method of original construction nor the length of time during which a public way has been in use there are any superficial indications of a defect, or any reasonable ground to apprehend that through structural changes beneath the surface due to the subsidence of culverts, bridges, drains or sewers, which may have become out of repair, the roadbed may suddenly give way, causing injuries to travellers, the duty of reasonable supervision is not as matter of law shown to have been neglected, and the city or town is not legally chargeable with notice of concealed conditions which may render the way unsafe. Miller v. North Adams, 182 Mass. 569. Comerford v. Boston, 187 Mass. 564, 567. Campbell v. Boston, 189 Mass. 7,10,11, and cases cited. See Young v. Snell, 200 Mass. 242, 245.
The notice having designated a particular place where the break occurred, the defendant excepted to the admission of the testimony of the foreman of the gas company, that, the defendant, having been notified of a break in the surface from the collapse of the sewer at a point about fifteen feet distant, it made suitable repairs, and that the boards then appeared to be broken and rotten. The sewer had not been relaid or repaired during a period of eighteen years, and the tendency of planks or boards to decay when placed under ground-is a matter of common knowledge. If the walls had given way where the repairs were made, because the boards had become rotten, the defendant had not only notice of the defect which it remedied, but knowledge of conditions from which it should have inferred that there was a reasonable probability that in the immediate vicinity the walls of the sewer upon further examination might be found to be unsound. The evidence, therefore, was admissible. Post v. Boston, 141 Mass. 189. Campbell v. Boston, 189 Mass. 7. Harrigan v. Worcester, 198 Mass. 354. Winship v. Boston, 201 Mass. 273.
The refusal to order a verdict for the defendant was right, and the instructions given to the jury at the request of the plaintiff correctly stated the law.
Exceptions overruled.