Perth Bore Water Testing for Irrigation — Lawn, Garden & Rural Use
Perth has more residential bores per capita than any other Australian capital city. The Water Corporation estimates that Perth households collectively pump billions of litres of groundwater for outdoor use every year — lawns, gardens, vegetable patches, and in rural areas, pasture and crops.
Most of these bores have never been tested.
This article is specifically about bore water used for irrigation — lawn care, garden watering, agricultural use, and stock water. If you're using your bore for drinking or household purposes, see our Perth bore water drinking water safety guide instead.
Why Perth bore water irrigation testing matters
Most Perth bore water problems don't announce themselves immediately. A bore that delivers perfectly adequate water in year one can be quietly degrading your soil, blocking your drippers, staining your infrastructure, and stressing your lawn — and the cause won't be obvious until the damage is visible.
The most common irrigation water problems in Perth's Superficial Aquifer are:
Iron staining — orange-brown deposits on pavers, fencing, shed roofing, pool surrounds, and any surface contacted by irrigation spray. One of the most common bore water complaints across metropolitan Perth, particularly in the northern and southern suburbs
Salinity and sodium — elevated electrical conductivity and sodium suppress growth in salt-sensitive grass varieties and garden plants, reduce pasture yield, and accumulate in the soil profile with every irrigation cycle
Dripper and emitter blockage — high hardness and bicarbonate cause progressive mineral scale inside drip irrigation fittings, creating dry patches and uneven coverage
Lawn browning and poor establishment — often attributed to watering schedule or fertiliser, but frequently a direct consequence of EC and sodium levels in the bore water being applied
The difficulty is that none of these problems are visible in the water itself. Saline water looks identical to fresh water. High-iron water may run clear from the tap and only stain once it contacts surfaces and oxidises. Knowing what's in your bore water before problems develop is significantly cheaper than treating the consequences after they do.
Perth's Superficial Aquifer — what affects irrigation quality
The Superficial Aquifer underlies most of the Swan Coastal Plain from Mandurah to Two Rocks. It's an unconfined aquifer — rainfall percolates directly through Perth's sandy soils and recharges the water table, which is why bore installation is straightforward and cost-effective across most of the metropolitan area.
The chemistry of water drawn from this aquifer varies significantly by location, depth, and local land use history:
Iron and manganese
Iron is naturally present across much of the Swan Coastal Plain as a result of the iron-rich sandy soils and lateritic geology of the region. Reducing conditions in the aquifer — where dissolved oxygen is low — mobilise iron into the water column in its soluble ferrous form. When this water contacts air at the surface it oxidises to insoluble ferric iron, which precipitates as the characteristic orange-brown stain.
The ANZECC/ARMCANZ irrigation water quality guideline for iron is 0.3 mg/L — concentrations above this level are associated with visible staining. Many Perth bores operate well above this threshold without the owner being aware of the actual iron concentration.
Manganese causes similar but darker staining — black-brown deposits on surfaces and inside irrigation fittings. The ANZECC guideline for manganese in irrigation water is 0.2 mg/L.
Salinity and electrical conductivity
Electrical conductivity (EC) is the primary measure of overall salinity in irrigation water. The ANZECC guideline threshold for irrigation water is 800 µS/cm for most crops and lawn grasses — above this level, growth suppression becomes increasingly likely in salt-sensitive species.
Perth's coastal aquifers are generally more saline than inland aquifers due to proximity to seawater and historical marine sediment deposits. In some coastal suburb bores, EC can reach levels that significantly limit plant growth even in established lawns. EC also compounds over time — every irrigation cycle deposits a small amount of salt in the soil profile, and without adequate rainfall leaching, salinity builds season after season.
Sodium and SAR
Sodium is particularly damaging to soil structure under sustained irrigation. High sodium displaces calcium and magnesium from soil particles, causing clay dispersion, reduced pore space, and poor drainage — a condition known as sodicity. The Sodium Adsorption Ratio (SAR) is the calculated index used to assess sodium hazard in irrigation water. It is calculated from the measured sodium, calcium, and magnesium concentrations and expressed as a ratio.
The ANZECC guideline threshold for SAR in irrigation water is 6.0 for most soil types. Above this level, soil structural degradation becomes increasingly likely under continued irrigation. Many Perth bores in coastal and low-lying areas deliver water with SAR values approaching or exceeding this threshold.
Hardness and bicarbonate
Total hardness — the combined calcium and magnesium content — determines the scaling potential of irrigation water. High hardness combined with elevated bicarbonate drives carbonate precipitation inside irrigation fittings when water contacts air or changes temperature. The result is progressive emitter blockage in drip and micro-spray systems.
The ANZECC guideline for bicarbonate in irrigation water is 400 mg/L as HCO3. Above this level, carbonate precipitation becomes increasingly likely without acid injection or emitter maintenance. Perth's carbonate-rich soils mean bicarbonate can be elevated even in bores with otherwise adequate chemistry.
Nutrients — fertility and contamination signals
Nitrate, nitrite, and ammonia in bore water can indicate agricultural fertiliser leaching, septic system influence, or natural soil nitrogen cycling. In an irrigation context, elevated nitrogen adds to the nutrient load already applied through fertiliser programs — which can drive excessive vegetative growth, thatch accumulation in lawns, and algal growth in dams and ponds.
Potassium is also measured as an indicator of soil fertility balance and potential toxicity at very high concentrations in sensitive crops.
Boron
Boron is naturally present in some Perth aquifer units and is highly toxic to certain crops and garden plants at concentrations that have no visible effect on lawns or tolerant species. The ANZECC guideline for boron in irrigation water varies by crop sensitivity — for sensitive species it is as low as 0.5 mg/L, for tolerant species up to 6.0 mg/L. Stone fruits, roses, and many vegetable crops are boron-sensitive. Lawn grasses are generally tolerant.
Hydrogen sulfide
The characteristic rotten-egg smell occasionally reported in Perth bore water is hydrogen sulfide — a gas produced by sulfate-reducing bacteria in anaerobic aquifer conditions. At elevated concentrations it is corrosive to metal fittings and irrigation infrastructure and can cause rapid blockage of emitters through sulfur precipitation.
What the test covers
The Bore Irrigation Screen tests 21 parameters covering the full range of irrigation water quality concerns:
Salinity and dissolved solids — Electrical Conductivity, Total Dissolved Solids, Chloride, Sulphate
Metals and staining — Iron, Manganese, Boron, Apparent Colour, Turbidity
Soil structure and hardness — Sodium, SAR (calculated), Total Hardness, Calcium, Magnesium, Bicarbonate, Alkalinity
Nutrients and contamination — pH, Nitrate, Nitrite, Ammonia, Potassium, Hydrogen Sulfide
All results are compared against ANZECC/ARMCANZ 2000 irrigation water quality guideline values — not drinking water standards. SAR is calculated from your measured sodium, calcium, and magnesium results and reported alongside the guideline threshold for your soil type context.
Choose your test
Bore Irrigation Screen — A$349
21 parameters benchmarked against ANZECC irrigation guidelines. The right starting point for any Perth residential or rural bore used for lawn, garden, or agricultural irrigation where drinking water safety is not a concern.
Includes: sampling kit delivered to your door, pre-paid return satchel, NATA-accredited laboratory analysis, SAR calculated from results, plain-language PDF report benchmarked against ANZECC guidelines, NATA certificate of analysis.
Suitable for: residential garden bores, rural irrigation, dams and catchments, drip and spray irrigation systems, stock water assessment, hydroponic source water.
Bore Irrigation Screen + E. coli — A$449
Everything in the Bore Irrigation Screen, plus E. coli and Thermotolerant Coliforms. Recommended where irrigation water contacts edible crops, vegetable gardens, or fruit trees, or where stock water safety is a concern.
Includes everything above, plus: cold-chain sample kit with insulated bag and ice pack, express return post for 24-hour holding time, microbiology analysis, faecal contamination risk assessment, combined irrigation and microbiology report.
What your report shows
Each parameter is reported alongside the relevant ANZECC/ARMCANZ guideline value and assessed as below, approaching, or exceeds.
Where a parameter approaches or exceeds a guideline level, a factual note describes the physical effect associated with that concentration in irrigation contexts — staining risk, growth suppression potential, emitter blockage likelihood, or soil structural impact. The report does not recommend specific products or treatment systems — it provides the data you need to make an informed decision about your water and your irrigation setup.
What to do with your results
Iron and manganese exceeding guidelines — oxidising filters, aeration systems, and injection treatment are the main approaches for iron removal from irrigation supply. At lower concentrations, adjusting spray timing to avoid contact with infrastructure and increasing rinse frequency reduces staining impact.
EC approaching or exceeding guideline — blending with scheme water or rainwater reduces overall salinity load. Adjusting irrigation scheduling to apply less frequently and more deeply reduces surface salt accumulation. Selecting salt-tolerant grass varieties and plants reduces visible impact.
High SAR — gypsum application to the soil can improve soil structure under high-sodium irrigation by replacing sodium with calcium. Professional soil assessment is worthwhile where SAR is significantly elevated.
High bicarbonate and hardness — acid injection systems reduce pH and prevent carbonate precipitation in drip systems. Regular emitter flushing and maintenance extends system life.
Positive E. coli (with microbiology add-on) — bore casing inspection and any necessary repairs, followed by disinfection. Do not use water from bores with positive E. coli results on edible crops or for stock drinking without treatment.
How often should I test my irrigation bore
For residential garden bores, testing every 2–3 years is appropriate unless you notice changes in performance, staining, or plant health. You should also test:
When first commissioning a bore or purchasing a property with an existing bore
If iron staining or lawn browning develops or worsens
After any bore maintenance, pump replacement, or pressure system work
If the bore is being used on a new crop variety or expanded to a new area
After nearby development or land use changes
For rural and agricultural bores where irrigation quality directly affects crop yield and income, annual testing is recommended.
Also using this bore for drinking?
An irrigation screen is not an assessment of drinking water safety. The parameters and guideline values used for irrigation assessment are completely different from those relevant to drinking water safety. An irrigation screen does not test for the contaminants — including E. coli at full sensitivity, arsenic, lead, PFAS, and nitrate at health-relevant thresholds — that determine whether bore water is safe to drink.
If you use your bore for any household drinking purpose, see our bore water drinking safety kits which are benchmarked against the Australian Drinking Water Guidelines.
Frequently asked questions
My lawn looks fine. Do I still need to test?
Problems from poor irrigation water quality often develop slowly and are attributed to other causes — fertiliser, watering schedule, soil compaction, or shade. A lawn that established well in year one can show progressive decline from salt accumulation, sodium soil damage, or manganese toxicity over several seasons. Testing before problems develop is significantly cheaper than addressing them after.
Can I use the same sample for irrigation and drinking water testing?
No — irrigation and drinking water testing require different sample collection protocols, different bottle types, and in the case of microbiology, different preservation requirements. They are separate products with separate kits.
My bore smells like rotten eggs. What is that?
Rotten egg smell in bore water is hydrogen sulfide — produced by sulfate-reducing bacteria in low-oxygen aquifer conditions. It is common in some Perth aquifer zones. The Bore Irrigation Screen includes hydrogen sulfide as a tested parameter. At elevated concentrations it is corrosive to metal irrigation fittings and can cause blockage through sulfur precipitation on emitters.
Does the irrigation screen tell me if my water is suitable for vegetables?
The screen reports your results against ANZECC/ARMCANZ guideline thresholds, which include sensitivity ratings for different crop types. The report will note where parameters exceed thresholds relevant to sensitive crops. For edible gardens we recommend adding the E. coli screen — the irrigation screen without microbiology does not assess faecal contamination risk.
What is SAR and why does it matter?
SAR — Sodium Adsorption Ratio — is a calculated index that predicts sodium's effect on soil structure under sustained irrigation. High sodium displaces calcium and magnesium from soil particles, causing clay dispersion and reducing drainage and aeration. A bore delivering water with elevated SAR can progressively degrade soil structure even if the lawn or garden appears healthy in the short term. SAR is calculated from your measured sodium, calcium, and magnesium concentrations and compared against the ANZECC guideline of 6.0.
Safe Water Lab provides mail-order bore water irrigation testing for Perth and Western Australia using NATA-accredited laboratory analysis (Accreditation No. 1261). All results are benchmarked against ANZECC/ARMCANZ 2000 irrigation water quality guidelines. View irrigation testing kits →