OSTDS 2025/2026 Exam Questions with
Detailed Verified Answers (100% Correct
Answers) | Already Graded A+
Net Usable Lot Area 64E-6.005 (7) - 🧠ANSWER ✔✔Net usable area is
used to calculate the authorized sewage flow for the subject property (total
lot size)
*Surface water bodies shall not be included in total lot size calculations
Unobstructed Area Determinations - 🧠ANSWER ✔✔Minimum 1.5 X the DF
area
*does not include any tanks nor 18 inches from tank
*area between drain trenches shall be included in the unobstructed area
calculation
Calculate 200 gdp per day for BED configuration & Calculate the
unobstructed area - 🧠ANSWER ✔✔334/0.60 sq.ft. DF
Unobstructed area 334 x 1.5 = 500 sqft
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
1
, Calculate 200 gdp per day for TRENCH configuration & Calculate the
unobstructed area - 🧠ANSWER ✔✔250/0.80= 250 sq. ft. DF
Unobstructed area = (250 x 1.5) 375 sqft
Benchmark - 🧠ANSWER ✔✔A mark on a permanent object of
predetermined position and elevation used as a reference point
Reference Point - 🧠ANSWER ✔✔A specific location (in a plan elevation) to
which measurements are referred
Setback to private potable wells - 🧠ANSWER ✔✔75 ft
Setback to non-potable - 🧠ANSWER ✔✔50 ft
Setback to public drinking water wells - 🧠ANSWER ✔✔100-200 ft
Setback to monitoring wells - 🧠ANSWER ✔✔5 ft
Setback to storm sewer pipe - 🧠ANSWER ✔✔10ft max possible, not less
than <5 ft
Setback to dry-ponds/drainage features, retention areas - 🧠ANSWER
✔✔15 ft
Setback to potable water lines - 🧠ANSWER ✔✔10 ft not less than 2 ft
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
2
Detailed Verified Answers (100% Correct
Answers) | Already Graded A+
Net Usable Lot Area 64E-6.005 (7) - 🧠ANSWER ✔✔Net usable area is
used to calculate the authorized sewage flow for the subject property (total
lot size)
*Surface water bodies shall not be included in total lot size calculations
Unobstructed Area Determinations - 🧠ANSWER ✔✔Minimum 1.5 X the DF
area
*does not include any tanks nor 18 inches from tank
*area between drain trenches shall be included in the unobstructed area
calculation
Calculate 200 gdp per day for BED configuration & Calculate the
unobstructed area - 🧠ANSWER ✔✔334/0.60 sq.ft. DF
Unobstructed area 334 x 1.5 = 500 sqft
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
1
, Calculate 200 gdp per day for TRENCH configuration & Calculate the
unobstructed area - 🧠ANSWER ✔✔250/0.80= 250 sq. ft. DF
Unobstructed area = (250 x 1.5) 375 sqft
Benchmark - 🧠ANSWER ✔✔A mark on a permanent object of
predetermined position and elevation used as a reference point
Reference Point - 🧠ANSWER ✔✔A specific location (in a plan elevation) to
which measurements are referred
Setback to private potable wells - 🧠ANSWER ✔✔75 ft
Setback to non-potable - 🧠ANSWER ✔✔50 ft
Setback to public drinking water wells - 🧠ANSWER ✔✔100-200 ft
Setback to monitoring wells - 🧠ANSWER ✔✔5 ft
Setback to storm sewer pipe - 🧠ANSWER ✔✔10ft max possible, not less
than <5 ft
Setback to dry-ponds/drainage features, retention areas - 🧠ANSWER
✔✔15 ft
Setback to potable water lines - 🧠ANSWER ✔✔10 ft not less than 2 ft
COPYRIGHT©JOSHCLAY 2025/2026. YEAR PUBLISHED 2025. COMPANY REGISTRATION NUMBER: 619652435. TERMS OF USE. PRIVACY
STATEMENT. ALL RIGHTS RESERVED
2
