Mr. O. P. Dennis, office of Proctor & Dennis, architects and superintendents, Tacoma, Wash., writes:

"I wish to ask you a question or two, trusting you will give me the desired information.

"First, I will state our city plumbing ordinance provides that there shall be no running trap (or any other kind) in sewer or soil pipe between street sewer and fixtures in house (that is not mentioning traps connected with fixtures). But the ordinance provides that conductors from the roof must connect with the sewer. This I think all right. What I wish to know is if it is not better to have a running trap at a point just outside of the building, and then at a point between sewer and trap connect the conductor pipe. Lastly, what are the rules in New York City in regard to making sewer connections for a double building, or rows of connected houses ? Is it the custom to make separate connections, or is one connection allowed for two or more where they are owned by the same owner ?"

[As often explained in these columns, it is safer to place the main trap on the house drain between the sewer and the house system either just outside or inside of the house wall, as may be most convenient. A running trap is not, however, a good form of trap. It is better to use a half-S trap with a tee branch, so that the bottom of the inlet is a few inches above the water seal in the trap. (See illustration on page 218 of "House Drainage and Plumbing Problems.") If it is desired to ventilate the town sewers by pipes running up on the outside of the house walls, the leaders from the roof may be connected outside of this main trap. These pipes, however, should be of cast iron and made perfectly tight, especial care being taken that no leakage of gas can occur near windows.

The regulations of New York require that each house shall have a separate sewer connection. This is a wise provision, and should be insisted on everywhere. This regulation is without regard to the size of the house, and is intended to protect each householder, so that no single householder who may keep his drains in order shall be subject to annoyance or risk from the negligence of any other householder. It is also a wise provision, from the fact, that though one owner may build several adjoining houses, they usually in time become the property of different owners.]