H. R. Richardson, of Hackensack, N. J., writes: "Will you inform me of some way to prevent back water from sewer beside using a back-water trap or valve? The accompanying sketch is the plan of some work which I have done, and it gives me considerable trouble. When the work was first put in I did not use the valve A and the water backed up in the cellar drain, causing a considerable nuisance. I then put in the valve A, which worked very well, as nothing but water passes through it. But I still found another nuisance; as I had stopped the water from entering cellar drains, it took another course, following the main soil pipe and coming out of servants' closet C. Now I thought of putting another valve at B, the same as I did at A, but as watercloset refuse is to pass through it I am opposed to using a valve like A, as there is a danger of its stopping or preventing it from working. If you can in-form me of some other plan you will confer a great favor to a constant reader of your valuable paper."

[It is impossible to keep back water out of a cellar or house drain without the use of some sort of a valve trap, and we should advise the substitution of such a valve for the running trap shown on your sketch near the front wall. You will find some backwater traps described in our advertising columns. It is a mistake to connect the cellar drains which are to remove ground water from the house with your sewage drain as appears to have been done. At seasons when there is no ground water direct communication is made with sewer pipes and sewage matter, which should be avoided. In "House Drainage and Plumbing Problems," which is a collection of articles from this journal, you will see two plans illustrated on pages 45 and 47, under title of "Ground-Water Drainage of Country House," and "Ground-Water Drainage, City House," that will suggest a safer method of removing ground water.

Finally, cannot your town authorities prevent the water from backing up in their sewer? Possibly this action may be due to some local defect that could be corrected.]