Question? Just ask us!
Free Encyclopedia of Building & Environmental Inspection, Testing, Diagnosis, Repair
InspectAPedia ® Home
WATER PUMPS, TANKS, TESTS, WELLS, REPAIRS
WATER CONSERVATION MEASURES
WATER CONTAMINANT LEVELS
WATER FILTERS, HOME USE
WATER HAMMER NOISE DIAGNOSE & CURE
WATER ODORS, CAUSE CURE
WATER PUMP REPAIR GUIDE
WATER PRESSURE LOSS DIAGNOSIS & REPAIR
WATER PUMP SHORT CYCLING
WATER SOFTENERS & CONDITIONERS
WATER TANK REPAIR PROCEDURES
WATER TANK: USES, TROUBLESHOOTING
WATER TESTS, CONTAMINANTS, TREATMENT
WATER TREATMENT EQUIPMENT CHOICES
WELLS CISTERNS & SPRINGS
WELL CHLORINATION & DISINFECTION
WELL FLOW RATE
WELL WATER PRESSURE DIAGNOSIS
WELL YIELD IMPROVEMENT
WINTERIZE A BUILDING
Well clearances and distances to other site features: This document provides a table giving the required distances between wells and other site features which could affect drinking water quality - potential sources of well contamination. If a property takes its drinking water supply from a site where these distances are violated, or where there are other reasons to be concerned for water quality, the well water should be tested regularly.
Our procedure is to perform an extensive broad-spectrum water test, depending on what we know about the property, its history, and its location. We're not only concerned for bacterial contamination - the common "water coliform test". Our page top photo shows a well located in the basement of a home. Is this OK?
Green links show where you are. © Copyright 2014 InspectApedia.com, All Rights Reserved.
In addition to considering the actual well clearances you observe at a property you should decide whether addtiona or specific water contamination tests are thus appropriate. Here are some examples of how well setback distances affect water testing advice.
Well sketch at left courtesy of Carson Dunlop Associates. [Click to enlarge any image]
Water serving a farmhouse near an apple orchard might get extra testing for pesticides or fertilizers. Water at a property where fuels or heating oil were stored close to a well may need water testing for petroleum products.
Site features which risk well contamination include nearby cesspools, drywells (for gray water), soils which have been chemically treated, such as to provide a termite barrier, farm buildings, manure piles, livestock yards, silos, and fertilizer storage.
Consideration should also be given to surface water runoff from adjoining properties, orchards (pesticide-treated), highways and roads, or properties with above ground or buried storage tanks such as for heating oil, fuel oil, or farm and orchard chemicals.
The table below gives distance requirements between drinking water supply wells and septic systems, farm buildings, chemically-treated soils (such as for termites) and other property features which may affect drinking water quality. Common guidelines require at least 50' clearance distance between a well and a septic system tank or 150' between a well and a septic drainfield or leaching bed but you will see that different authorities may recommend different distances.
US-HUD/FHA, Canadian, & U.K. Well Clearance Distances
Local soil and rock conditions can make these "rules of thumb" unreliable. See the U.S. "One and Two Family Dwelling Code, Section P-2510-Combined Seepage Pits and Disposal Fields," and Table P-2504, "Location of Sewage Disposal System." Other references are cited at the end of this table. A separate table SEPTIC CLEARANCE DISTANCES gives the required distances between septic systems and other site features.
WELL & SEPTIC SYSTEM CLEARANCE DISTANCES - TABLE NOTES:
HUD distances to septic drainfield, and similar components changed from 75' to 100' prior to 10/2009 - thanks to a reader [anonymous by request].
-1 Distance from source of pollution - proposed construction, US Dept. of Housing and Urban Development, FHA, Local acceptable standard No. 3, June 18, 1992, Ref. Hud Handbook 4910.1 Chg 1, Appendix K, Pg K-27
(SUP1) This clearance may be increased or decreased depending upon soil and rock penetrated by the well and aquifer conditions. The clearance may be increased in creviced limestone and permeable strata of gravel and sand. The clearance may be reduced to 50 ft. only where the ground surface is effectively separated from the water bearing formation by an extensive, continuous and impervious strata of clay, hardpan, or rock. The well shall be constructed so as to prevent the entrance of surface water and contaminants.
(SUP2) The recommendations or requirements of the local health authority shall apply.
(SUP3) This clearance may be reduced to 15 feet only where the ground surface is effectively separated from the water bearing formation by an extensive, continuous and impervious strata of clay, hardpan, or rock.
(*EP) For Existing Properties. If the locality permits distance requirements less than those prescribed by FHA, the property may be considered eligible for a mortgage insured by FHA provided that the lender submits evidence in the case binder that the subject property is in compliance with the applicable local or state distance requirements and meets the conditions stated in Mortgagee Letter 2002-25.
These tables give typical required clearances for septic tank, soil absorption system (SAS), etc. but you will see that different authorities may recommend different distances. These distances are for conventional onsite waste disposal systems which specify clearances presuming that effluent is being disposed-of after minimal treatment such as is received by a septic tank or cesspool. Advanced onsite wastewater treatment systems, such as those described by Jantrania and Gross (2006), permit substantial reduction in these clearances, depending on the level of treatment achieved.
Is your well located on your property?
Individual Water Systems/Wells should be located on the subject property site. If not, they must be on an adjacent property, and evidence of water rights and recorded maintenance agreement must be provided for acceptance of the well as the primary source of water for an FHA insured property.
Is a Hand Dug or Driven Point Well Acceptable to HUD?
New wells must be drilled, no less than 20 feet deep, and cased. Casing should be steel or other casing material that is durable, leak-proof, and acceptable to (either) the local health authority and (or) the trade or profession licensed to drill and repair wells in the local jurisdiction.
Additional information on new wells, pumps, and storage tanks construction information may be referenced from HUD Handbook 4910.1, Appendix K and 24CFR 200.926d(f) [DJF note: we removed the link to this CFR citation because it is not working at the HUD site; accurate link citation needed]
CISTERNS:HUD Handbook 4150.2 Section 3-6 indicates that properties served by cisterns are not acceptable for mortgage insurance. However, the HOCs have the authority to consider waivers in areas where cisterns are typical.
Our photo (above left) shows a hybrid system: this outdoor cistern is filled by pumping from an open casing in a drilled well that was inserted in the bottom of a dug well that went "dry" (photo, above right).
As will be apparent to readers, both the open top of this cistern and the open casing in the bottom of the dug well are sources of water contamination.
See CISTERNS for more information about this water source.
Is Water Purification Equipment Required by or Acceptable to HUD for HUD Financing?
Individual Residential Water Purification Equipment - If a property is otherwise eligible for insurance but does not have access to a continuing supply of safe and potable water without the use of a water purification system, the requirements in Mortgagee Letter 1992-18 must be satisfied.
Our photo (left) shows a UV light water treatment system installed to address low-level bacterial contamination in a private water supply. See WATER TREATMENT EQUIPMENT CHOICES for details. The HUD letter states that effective 5 June 1992, [we quote key portions of the document]:
U.S. Environmental Protection Agency EPA Well Clearance Distances
Green link shows where you are in this article series.
Frequently Asked Questions (FAQs) about clearance distances for water wells
Questions & answers or comments about the required clearance distance between wells, septic systems and other site features.
Check the FAQs just above, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Search the InspectApedia website
HTML Comment Box is loading comments...
Technical Reviewers & References
Related Topics, found near the top of this page suggest articles closely related to this one.