Water Quality for Horses
Understanding Bacterial Counts
Table of Contents
- Introduction
- Assessing Water Quality:
- Total Bacteria Count
- Total Coliform Bacteria
- Fecal Coliforms
Introduction
Water used on horse farms can be supplied from a private well, a
public water source, a river, pond or lake. Public water suppliers
e.g. municipal water suppliers are responsible for ensuring the quality
of the water being supplied to you. If you own your well, it is your
responsibility to ensure water quality for you and your animals and
to ensure the safety of the ground water.
Drinking water is normally tested for the presence or absence of
two groups of bacteria; total coliforms and fecal coliforms. These
bacteria are considered indicators of the presence of animal wastes
and sewage. Fecal coliforms are present in large numbers in intestinal
contents of humans and warm blooded animals. They die fairly easily
once they are outside of the body. Their presence in well water indicates
relatively recent contamination and a short distance of travel. Water
containing f ecal coliform bacteria should not be consumed without
adequate treatment e.g. boiling or disinfection (1).
The Ministry of Health provides bacterial analysis of water in Ontario.
Contact your local health unit for sterile bottles and sampling and
handling instructions. Water testing should be done on a regular basis
at different times of the year and during different rainfall situations.
If there is a problem, a more specific second test should be done
to differentiate, for example, if the high coliform count is fecal
coliforms from animal or human waste. Tests for specific chemicals,
toxic metals, pesticides, herbicides, solvents or organic compounds
can also be done.
Assessing Water Quality:
Total Bacteria Count
Water intended for livestock should have a total bacteria count
of less than 200 bacteria per 100 ml. of water but, based on research
literature and field experience, livestock can tolerate levels up
to 1 million bacteria per 100 ml. of water (2).
Total Coliform Bacteria
The Ontario Drinking Water Objective for human consumption states
that total coliform bacteria should not be present at 5 or more coliform
bacteria per 100 ml. of water when using the Most Probable Number
(MPN) test or Membrane Filter (MF) test and should not be present
within 48 hours when using the Presence-Absence (P-A) test (3). Calves
can contract scours (diarrhea) when drinking water containing coliform
bacteria counts of more than 1 coliform bacteria per 100 ml. of water.
However, older cattle can tolerate concentrations of 20-50 coliforms
per 100 ml. of water with no adverse affects (4) (5).
Fecal Coliforms
Fecal Coliforms should not be detected in any sample for any of
the above tests.
As a general recommendation, the minimum distance from any potential
source of contamination, e.g. septic tank, manure storage or live
animals, should be 50 feet for a drilled well and at least 100 feet
for a dug well or surface water source such as a pond.
